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Introductory sentence[edit]

"Like reptiles and birds, mammals are amniotes that breath air with complex eggs." Is "complex eggs" a technical term or simply a mistake? If it is the former: the sentence is rather confusing to a non-expert reader. — Preceding unsigned comment added by (talk) 13:19, 1 December 2012 (UTC)

Article organization[edit]

Looking at the current version of the article, I believe the following text should be moved from "Reproductive system" to "Distinguishing features":

"Although all mammals are endothermic, so are birds, so this too is not a defining feature.

Mammals have sweat glands, a defining feature present only in mammals. Some of these glands produce milk (in what are called mammary glands), a liquid used by newborns as their primary source of nutrition. The monotremes branched from other mammals early on, and do not have the nipples seem in most mammals, but they do have mammary glands. Most mammals are terrestrial, but some are aquatic, including sirenia, (manatees and dugongs), and the cetaceans, (dolphins and whales). Whales are the largest of all animals. There are semi-aquatic mammalian species such as seals which come to land to breed but spend most of the time in water."

Thank you! Smithbrenon 08:47, 9 September 2007 (UTC)

Gotcha. Leadwind (talk) 06:46, 22 November 2007 (UTC)

Could there possibly be a circulatory system "bullet"; something about how they have 4 chambered hearts, etc. —Preceding unsigned comment added by Lak9310 (talkcontribs) 14:00, 16 February 2010 (UTC)


This is so unbelievably unclear.Marcraymond (talk) 11:04, 18 May 2012 (UTC) 7:03 18 May 2012

I have a question concerning mammalian taxonomy. There are several classifications presented, including one that says: "Classification system used in related articles". However, it's a fact that most "related" articles already shifted to the genetic classification, which is more or less accepted as "valid" by the wikipedia community. As a result, I think that the classification "used in related articles" is obsolete and should therefore be removed. What is everybody's opinion on this? DaMatriX 20:15, 31 March 2007 (UTC)

How about updating it to reflect the related articles? - UtherSRG (talk) 21:06, 31 March 2007 (UTC)
Yes, that may be a good start. But how to review the "related articles"? Consider the fact that the total number of "related articles" can be quite hight, depending on the criteria one is using. DaMatriX 03:05, 1 April 2007 (UTC)
A few dozen. The taxonomy used in related articles only goes down to the various orders. - UtherSRG (talk) 12:06, 1 April 2007 (UTC)

Alright, but before we start we must descide exactly [i]which[/i] classification to use in extended articles. In the last week, I've already been updating some related articles, changing the taxonomy according to recent data. However, in doing so the current classification that's used in related articles is not consistent at this moment. Some issues that should be discussed before we resume are:

1) Are we using the molecular classification or not? In other words: do we use Laurasiatheria, Atlantogenata, Afrotheria and Euarchontoglires in all related articles, even those on individual orders (living or extinct)? If the answer is yes, any reference to certain clades that are now used in related articles should be removed. As a result, Ungulatomorpha, Archonta, Lipotyphla and several others have to be declared defunct on wikipedia and should not be used anymore. That descission will be very controversial en will receive much criticism by certain users, since not everyone is convinced that the molecular classification is valid. However, if that's the case than all reference to the molecular classification should be removed, and that's impossible: it is already been widely used in many articles. So what to do? We should choose one consistent classification, not shifting between two, depending which one is more convenient in a certain situation.

2) How do we make use of clades between that of Amniotes and Mammals? What place do we give Mammaliaformes? Do we make use of paraphyletic clades as Allotheria? And, most important: do we use the historical classification of deviding the amniotes in the classes Mammalia, Aves and Reptilia, or do we use the (cladistic more correct) classes Sauropsida and Synapsida instead? In that case, will Mammalia become a clade below that of a class, or do we blend both definitions? This will result in an definition of the biological class that is crappy form a taxonomic and cladistic point of view, but will be acceptable if we both want to make things as clear as possible for the average viewer AND want to make use of an clasistic approach, without losing compatibility with tradional views that people are familiar with?

Example: is this acceptable?

(unranked): Amniota > Class: Synapsida > Order: Therapsida > (unranked): Theriodontia > Suborder: Cynodontia > Class: Mammalia > Subclass: Theria etc

At first sight, people will answer: "no, you can't have a class that is part of another class and even part of an suborder". They are right from a cladistic point of view. However, if we use cladistics consistently, then the commonly known class of Mammalia will have to disappear from wikipedia. Personaly, I object to that, dispite the fact that I like to be consistent, but in this case the "traditional" view can not be completely ignored. However, if we choose to blend cladistics and tradional views (in order to make things understandable for all people), what rank do we give clades like Sauropsida and/or Mammaliaformes?

DaMatriX 21:49, 1 April 2007 (UTC)

Look at Primates. All major orders are listed, and all minor ones between the article subject and the next higher major rank. This is the general standard all taxoboxes are supposed to follow. This way the muddiness of higher relationships is hidden on the majority of articles, and it can be dealt with in the body of the appropriate articles. Furthermore, as long as modern scientists still use certain terminology (such as class Mammalia) then we should too. Note that order Insectivora is now on the outs and doesn't even appear in MSW3. - UtherSRG (talk) 23:54, 2 April 2007 (UTC)
Personally, I prefer using Benton's taxonomy from Vert. Paleo. at least down to class level (this is what we're doing on the reptile and amphibian articles, at least, and those on synapsids, so some continuity would be nice). He uses Classes Sauropsida, Synapsida, Aves, and Mammalia, with the former two marked as paraphyletic. I think this does a good job of drawing the arbitrary line at a logical point. Mammaliaformes is unranked under Class Synapsida, and contains Class Mammalia. If I recall correctly, the way that page is set up right now is a good "transition" between the two. I'm not sure if such a thing exists, but rather than cobble together a taxonomy of Mammalia from various recent sources, preference should be given to any at least fairly recent sources that provide a taxonomy of the entire class down to at least order level. Then individual sources can be used to determine the taxonomy of individual orders, etc. Dinoguy2 06:36, 3 April 2007 (UTC)
I think Mammal should present both an anatomy-based and a molecular phylogenetic taxonomy - if it omits either approach, readers who have seen the omitted approach elsewhere may either get confused or think Wikipedia does not know of that approach. Within each approach, the article should use a taxonomy from just one source - cobbling two or more together would risk confusion and would violate WP:OR. But the article should say (for both approaches) which / whose taxonomy it is following, and refer to others. The molecular phylogenetic taxonomy will be cladistic because all published versions are cladistic. Since I've read more paelontology than modern zoology, I'd prefer the anatomy-based taxonomy will be cladistic too, but I suspect that needs discussion.Philcha 23:36, 29 June 2007 (UTC)

Evolutionary history[edit]

FYI, there seems to be a new scientific viewpoint regarding the evolutionary history of the mammals [1]. Perhaps this article could benefit from mentioning these findings. --JianLi 05:13, 11 April 2007 (UTC)


I've been updating the evolution section, but this section has become too large - at least to my opinion. Should I create a new article titled Evolution of Mammals? DaMatriX 00:46, 22 April 2007 (UTC)

Source for taxon numbers?[edit]

What exactly is the source for "5,800 species, 1,200 genera, 152 families, 46 orders" in the lead? I ask because the Animal Diversity Web instead gives 5,000 species and 26 orders. If these numbers include extinct taxa then perhaps it should be mentioned to avoid confusion. Enoktalk 19:36, 20 May 2007 (UTC)

46 orders, it's impossible. There are 28. (Source: ITIS) . Ba'Gamnan | Talk 12:08, 25 May 2007 (UTC)
Mammal Species of the World lists 28 as well. - UtherSRG (talk) 11:02, 25 May 2007 (UTC)
I'm wrong. MSW3 says 5418 species, 1231 genera, 153 families, 29 orders. However, I know that several new species were described since its publication. - UtherSRG (talk) 12:07, 25 May 2007 (UTC)
But in this (945 KB, MS Excel format, MSW), there are 28 orders. Ba'Gamnan | Talk 14:19, 25 May 2007 (UTC)
Yes, I grabbed the same Excel file from the MSW page:
  1. Monotremata
  2. Didelphimorphia
  3. Paucituberculata
  4. Microbiotheria
  5. Notoryctemorphia
  6. Dasyuromorphia
  7. Peramelemorphia
  8. Diprotodontia
  9. Afrosoricida
  10. Macroscelidea
  11. Tubulidentata
  12. Hyracoidea
  13. Proboscidea
  14. Sirenia
  15. Cingulata
  16. Pilosa
  17. Scandentia
  18. Dermoptera
  19. Primates
  20. Rodentia
  21. Lagomorpha
  22. Erinaceomorpha
  23. Soricomorpha
  24. Chiroptera
  25. Pholidota
  26. Carnivora
  27. Perissodactyla
  28. Artiodactyla
  29. Cetacea
-UtherSRG (talk) 13:01, 25 May 2007 (UTC)

You're right, MSW says 29 orders. Ba'Gamnan | Talk 15:17, 25 May 2007 (UTC)

Evolution of mammals[edit]

I've added an article Evolution of mammals, because there's too much content to squeeze into the Mammal article. Please review and comment.

Once there's a reasonable degree of agreement about Evolution of mammals, I propose to reduce the "Evolution" section of Mammal to a link to and brief summary of Evolution of mammals.Philcha 11:39, 27 June 2007 (UTC)

Ooh wow, great job! Aillema 11:00, 29 June 2007 (UTC)
I've now updated the "Evolution" section of Mammal as I proposed - except that it's not exactly brief, despite the fact that there's very little about Cenozoic mammals. At present I can't see how to make it any shorter without dropping important items which we can't assume the reader will already know. Any suggestions?Philcha 00:31, 4 August 2007 (UTC)

primary explanation for what mammals are[edit]

current text: Mammals (class Mammalia) are warm-blooded, vertebrate animals characterized by the presence of sweat glands, including milk producing sweat glands, and by the presence of: hair, three middle ear bones used in hearing, and a neocortex region in the brain. Most mammals also possess specialized teeth and utilize a placenta in the ontogeny. The mammalian brain regulates endothermic and circulatory systems, including a four-chambered heart.

This text is technically true but not what a typical reader needs. The lead is supposed to be especially accessible. See wp:lead.

proposed text: Mammals (class Mammalia) are warm-blooded vertebrates. Like reptiles and birds, mammals are amniotes, air-breathing vertebrates with complex eggs. They are distinguished from reptiles and birds by their hair, their sweat glands (including milk glands), their three middle ear bones used in hearing, and their neocortex (a region of the brain). The mammalian brain regulates endothermic and circulatory systems, including a four-chambered heart. Mammals are some of the largest, strongest, fastest, and most intelligent species on the planet, including whales, elephants, cats, and apes. The basic body type is a four-legged land-borne animal, but some mammals are adapted for life at sea, in the air, in the trees, or on two legs.

Comments? Leadwind (talk) 07:34, 22 November 2007 (UTC)

If anyone has a good reason for me not to move forward, speak up now. Leadwind (talk) 02:12, 27 November 2007 (UTC)
The only thing I'd take issue with here is use of "strongest"--what does that even mean? How would you measure or compare strength between different animals? I think an ant is far stronger, pound for pound, than any mammal, let alone vertebrate ;) Dinoguy2 (talk) 19:46, 27 November 2007 (UTC)
I could quibble, but it's a minor point, and I can drop "strongest." The important thing is that I want a naive reader to get the big picture. The lead is supposed to be accessible. There's already been some work on this part of the lead. I'll see about doing a little more. Leadwind (talk) 02:22, 28 November 2007 (UTC)

I support Leadwind's suggestion of a new lead paragraph to replace the two current first paragraphs. At the very least the "including milk-producing sweat glands" phrase is awkward. Mammary glands' origins need not be described here, just as the earbones are not described as modified jaw bones. If there is support I would change the text to Leadwind's with the deletion of strongest and the simple mention of mammaries. If there is no objection, I will change the reference to milk producing sweat glands to mammaries shortly. Kjaer (talk) 22:15, 18 November 2008 (UTC)

It seems that this good suggestion was never implemented. I have done this and done my best to include all internal wikipedia links. If there is any information that people feel is lacking, then please add it. — Preceding unsigned comment added by (talk) 16:17, 30 November 2012 (UTC)

Mammal speed[edit]

I am removing the characterization of mammals as especially fast. In a 100-meter dash, a cheetah has averaged 98 kilometers per hour (61 miles per hour), but it cannot sustain that speed; in contrast, a great snipe can average 97 km/h (60 mph) flying nonstop from Sweden to central Africa. Over short distances, a sailfish can manage 110 km/h (68 mph) while the spine-tailed swift has been clocked at 171 km/h (106 mph) in level flight. Of the four traditional vertebrate classes, only the reptiles cannot keep up; the fastest speed that has been observed for a reptile, a frightened leatherback turtle, was 35 km/h (22 mph). Peter Brown (talk) 03:30, 1 December 2012 (UTC)

Urgent question![edit]

what does † in †Allotheria* means. thanks, Sushant gupta (talk) 04:25, 10 April 2008 (UTC)

It means that the taxa is extinct. When the taxa is a species, it means the species is extinct. When the taxa is a higher rank than species (as in this case), it means all species in that taxa are extinct. - UtherSRG (talk) 06:05, 10 April 2008 (UTC)
thank you! :)) Sushant gupta (talk) 06:15, 10 April 2008 (UTC)

Mammal Definition[edit]

Hi, regarding the definition of a mammal. It says in the article a mammal is "characterized by the presence of sweat glands", however what about dolphins? They do not have sweat glands and are still mammals? Heres what i could find on the net regarding dolphin's lack of sweat glands(Look under the question,"How long can a dolphin stay out of water?"): [[2]] --Johnny 0 (talk) 15:01, 30 April 2008 (UTC)

Dolphins lost their sweat glands secondarily. Similarly, reptiles are characterized by having four limbs, even though snakes have lost theirs. Dinoguy2 (talk) 01:11, 1 May 2008 (UTC)
Female dolphins have mammary glands, which are thought to be modified sweat glands. Philcha (talk) 23:50, 7 July 2008 (UTC)

Strange Picture[edit]

There's a really weird picture in the subsection on intelligence - it's an old photo of some people in strange costumes, with the caption "Humans are the most intelligent mammals" Can someone please tell me why this is relevant? It seems to me to be a complete non sequitur. SnetskyCM (talk) 03:09, 7 September 2008 (UTC)

In the Reproduction section there is a picture of a goat and its mother. It is labelled as 'goat kid'. A goat calf or juvenile goat would be more appropriate than 'kid'. IMO, any takers to edit it for tone and correctness? —Preceding unsigned comment added by (talk) 20:49, 25 June 2010 (UTC)

"Kid" is the correct term for the young of a goat, equivalent to "lamb" for the young of a sheep, "foal" for horse etc. It has also been adopted by humans as a slang or casual word for their own young.( (talk) 14:33, 19 September 2011 (UTC))

Superorders of Mammals[edit]

I was looking at the box at the bottom of the page for mammals (I still cannot figure out what that is called), and the list of extant placental orders is very large and confusing to look at. Perhaps we should subdivide the placental group in the box into Euarchontoglires, Laurasiatheres, Xenarthrans, and Afrotheres, to make navigation among the different groups easier.Metalraptor (talk) 15:11, 3 November 2008 (UTC)

Interesting suggestion. The trouble is that the high-level taxonomy of mammals is still not settled - for exmaple we know pretty well what primates are, but there's debate about what are primates' nearest relatives; and AFAIK the controversy raised by the Afrotheria hypothesis has not been settled. -- Philcha (talk) 15:24, 3 November 2008 (UTC)

Article Lead[edit]

Hardyplants, you changed the lead to the following:

Mammals are a class of vertebrate animals called Mammalia. They are characterized by having sweat glands, hair, three middle ear bones used in hearing, having a neocortex region in the brain, and mammary glands, from which they derive their name.

All mammals, except for the five species of monotremes which lay eggs, give birth to live young. Most mammals also possess specialized teeth, and the largest group of mammals, the placentals, use a placenta during gestation. The mammalian brain regulates endothermic and circulatory systems, including a four-chambered heart.

But I reverted it. First, mammals are not "called" mammalia. Mammalia is their formal name. Second, if you want to change "the possession" to "having" that is fine, but you could simply say "are characterized by mammaries..." and leave out having or possession altogether. Also, mammaries, which traditionally define the class, should come first, rather than last. I kept the change of wording on monotremes.

The class is called mammalia, so mammals belong to the class mammalia. listing mammaries last was a way to end the sentance with the defining character, which makes it easer to remember in a long list. Hardyplants (talk) 23:41, 28 November 2008 (UTC)
Well, I think it is better now, but I still have a problem with saying that "Mammals belong to a class of vertebrate animals called Mammalia." It is a tautology - a restatement of the same thing without adding anything new. Before, in effect, we were saying "Mammals (aka, the class Mammalia) have yada yada yada." Now we are saying, in effect, "Mammals are mammalians. They have yada, yada, yada." But saying that mammals as a class are called Mammalia is really empty. I would prefer something like "Mammals, formally members of the Class Mammalia, are characterized..." This puts in the formal name without acting as if merely naming the group is providing additional information. It would be like having and article Cabs that starts "Cabs are vehicles that are called taxicabs." Look at the article Taxicab and you will see how you can mention the name while making the sentence about a meaningful definition. Kjaer (talk) 00:31, 29 November 2008 (UTC)
Mammal is a common name for a group, that group happens to have a scientific name mammalia. It says a lot, it means that the animals commonly called mammals are related and placed in the same class. Lets say we take another large group like plants, they belong to many different classes, so when we say that the large group of animals called mammals belong to one class we are communicating a lot of information. Hardyplants (talk) 01:01, 29 November 2008 (UTC)
This edit is wrong "Mammals (formally Mammalia)" I will let you sort that problem out but a common name is not the same as a scientific name and one does not replace another.Hardyplants (talk) 01:07, 29 November 2008 (UTC)
I think I understand your point. But:
mammal Look up mammal at 1826, Anglicized form of Mod.L. Mammalia (1773), coined 1758 by Linnaeus for the class of mammals, from neut. pl. of L.L. mammalis "of the breast," from L. mamma "breast," perhaps cognate with mamma.
The word mammal is simply the anglicization of Mammalia, coined less than two centuries ago. The groups are the same by definition, and the term mammal has always been a learned term, not a common name. The common name would, if the meaning hadn't changed, be "deer" < OE "deor" < IE *dher- which is cognate to the greek ther-ia (and the latin fer-ox or fer-alis) as well as the german (Säuge-)Tier. The common name would be beast, if there were one. But modern english does not have a non-learned name for furred beasts, just as it has no singular genderless word for cattle. Is the word "formally" throwing you off? I prefer it, but you could change it to scientific. Kjaer (talk) 03:02, 29 November 2008 (UTC)

The word mammal is simply the anglicization of Mammalia

Yes, mammal is the English common name for the Latinized Mammalia. The name of the class is Mammalia, this is a formal name describing a single entity which is a specific taxon. A mammal is a single entity (a single individual, or a single species), it can be pluralized when speaking about more than one mammal. Hardyplants (talk) 03:40, 29 November 2008 (UTC)

"Earliest appearances of features" seems to be a draft[edit]

Can some knowledgeable soul take a cut at cleaning this up? --Jhbdel (talk) 00:03, 9 December 2008 (UTC)

Largest Placental Orders[edit]

According to the unsourced fourth paragraph of the article, the carnivores and cetartiodactyla are the third and fourth largest orders of mammals. But according to Wilson and Reeder (see the pie chart) the soricomorphs and the primates are larger than either of these groups. I intend to chanve the wording to reflect this if no one objects. Here is the current, incorrect statement:

"Most mammals belong to the placental group. The four largest orders within the placental mammals are Rodentia (mice, rats, and other small, gnawing mammals), Chiroptera (bats), Carnivora (dogs, cats, bears, and other mammals that primarily eat meat), and Cetartiodactyla (including numerous herbivore species, such as deer, sheep, goats, and buffalos, plus whales). The human species is also a placental mammal, a member of the order Primates." Kjaer (talk) 05:36, 7 January 2009 (UTC)

I think its a bad idea, with out any reliable sources. [3] and [4] Hardyplants (talk) 04:56, 7 January 2009 (UTC)
I take it you mean that the current unsourced text is bad. If I replace it with the information from the Wilson and Reeder Pie Chart my only concern is that they separate the Cetacians and the Artiodactyls. I cannot tell from visual inspection if together they might outnumber the Primates, which I would list as the fourth largest group. Anyone know the actual species count? Anyone want to just delete the paragraph? I am for a rewrite, but am open to suggestions. Kjaer (talk) 05:36, 7 January 2009 (UTC)
I'm sorry, Hardyplants, I missed your references. The first doesn't indicate what it means by insectivores. And the number of Carnivores to Primates apparently varies with author. I am used to seeing Primates as the fourth largest group. I am leaning toward simply deleting the paragraph then. Kjaer (talk) 05:41, 7 January 2009 (UTC)

I am used to seeing Primates as the fourth largest group

what references are you using for this statement? Both of the sources I listed show the same ranking when it comes to primates, even though they use diffrent species counts. So for a genral line of text like "the four largest orders are..." they both stand in agreement. Hardyplants (talk) 05:49, 7 January 2009 (UTC)

My source cites Wilson and Reeder, so maybe my source is off. But this is not the point. The point isthat the texct here in this article is wrong, and I am willing to use any text you like, but the two texts you cited do not agree. One says primates are fifth, the other sixth. Kjaer (talk) 07:24, 7 January 2009 (UTC)

I have been using Wilson and Reeder and other wikipedia pages, as well as memory for ranking primates fourth. I am most happy to use whatever reliable sources we have. My central problem is that the paragraph as it stands is wrong by all accounts, since all sources identify "insectivores" of some definition as the third largest order. Your first source, Tax of Liv Org., says Rodents> Bats> Insectivores> Carnivores> Primates. But I do not know how it defines Insectivores or Carnivores (pinnipeds?), or how it treats Cetartiodactyla. Your second source lists Rodents> Bats> Eulipotyphlya (382)> Cetartiodactyla (88+196=284)> Carnivora (264)> Primates (256). Wilson and Reeder place primates as fourth, with no number in the pie chart, but they at least define Carnivora inclusively and Sorciomorpha exclusively. So, the position of Primates as fourth, fifth or sixth is up in the air. So, I am set on no specific ranking - but - I know the paragraph as it stands is wrong in all cases. Kjaer (talk) 06:47, 7 January 2009 (UTC)

"Wilson and Reeder place primates as fourth" - what page number? Hardyplants (talk) 07:10, 7 January 2009 (UTC)
I found the data:[5] Since there is major differences in the source ( they also use different criteria, extant and extant and recently extinct, and differences in how many orders there are) it would be useful to point out in our page there there is disagreement among experts as to how many species there are. Hardyplants (talk) 07:28, 7 January 2009 (UTC)

Okay, so how about we identify Rodents, Bats and Soricomorph insectivores as the three largest orders by all accounts, followed by carnivores, cetartiodactyls, and primates, but not necessarily in that order, depending on the source and definition used? Kjaer (talk) 07:47, 7 January 2009 (UTC)

I think you have found a good way to deal with it above, most people only care about the top three any way, and we can list our source for people to look up more details. So its a win - win. thanks. Hardyplants (talk) 17:12, 7 January 2009 (UTC)


Eomaia IMHO needs a couple of tweaks. I am not competent to make them myself.
(A) "Eomaia scansoria ... is an extinct mammal that may be one of the earliest ancestors of the eutheria yet to have been found." -- Fails WP:WEASEL, but how should we rephrase?
(B) "Eomaía was not a placental mammal. It was an early, primitive representative of the lineage of all placental mammals ..." -- IMHO we should add a note here of just what taxon we're talking about.
(C) "... including species of pig, elephant, horse, cat, dog, bat, mouse, rabbit, gorilla, chimpanzee, and human." -- Does this list mean anything? Eomaia is in the lineage of these mammals, but not others? Can we phrase this more gracefully?
- (Of course, please make any necessary edits at Eomaia, don't just discuss here.) -- (talk) 16:11, 7 January 2009 (UTC)

The word 'may' is not smuggling in some controversy, it simply reflects the fact that scientific hypotheses are provisional and speculative. But I agree with your other remarks. Kjaer (talk) 19:10, 15 January 2009 (UTC)

Done, see what you think. --Philcha (talk) 20:17, 15 January 2009 (UTC)

Content of template picture.[edit]

Why does the photo for the mammal template not include a sea mammal? I feel as though, as is, it doesn't adequately convey mammalian diversity on a level non-zoologists could appreciate. Perhaps replace the hedgehog with a whale? I don't want to step on the toes of hedgehog aficionados, but they're such an obscure, isolated, and quite frankly unimpressive species. I'm not a zoologist on even an amateur level and don't even claim to feign expertise, but wikipedia as an educational tool is of infinitely more use to the laity than to PhD candidates, and I feel a whale or seal would better serve to inspire general human interest.

Again, I'm not anything resembling an expert and I obviously expect disagreement, but do yourself a favour and explain your position in logical terms rather than throwing a tantrum of "WP:XX" shit. Wormwoodpoppies (talk) 00:41, 27 February 2009 (UTC)

No good reason. Feel free to put together a modified image (and upload it on Commons) if you think you think the current one isn't representative. Zetawoof(ζ) 07:34, 27 February 2009 (UTC)
It should rather have a marsupial and a monotreme too. Maybe replace the hedgehog with an echidna? FunkMonk (talk) 17:19, 4 March 2009 (UTC)

Removed paragraphs.[edit]

I just had to remove entire paragraphs, because they were copyvio's from the online Encyclopedia Brittanica. This greatly effects the quality of this article, but there is no other way solution than to start over :( --TheDJ (talkcontribs) 14:30, 3 March 2009 (UTC)


I'm not competent to correct but the introduction refers to "the three species of monotremes". The monotremes article refers to five extant monotreme species (although to three genera). Could somebody who knows something about mammals correct? Cphi (talk) 12:02, 12 March 2009 (UTC)


TIGERS LIVE IN COLD PLASES LIKE ASIA RUSSIA AND INDIA. —Preceding unsigned comment added by (talk) 00:05, 27 March 2009 (UTC)

The main image[edit]

Would it be possible to change the image to something else, that is more commonly thought of as a typical mammal? Such as a lion, elephant, dog, horse etc. A seal doesn't seem right to me. Aillema 01:38, 25 June 2007 (UTC)

I agree. The main image should be something four-legged and furry. I'll change it. --Arctic Gnome (talkcontribs) 15:40, 20 July 2007 (UTC)

As it currrently stands, the main image depicts four Laurasiatheres, the lion, giraffe, hedgehog and fruit bat. I would suggest that if we are going to depict four mammals, we go for maximum diversity. I suggest a monotreme, a marsupial (perhaps non-Australian, since Monotremes are Australian) a bat and a cetacean, or a proboscidean, to show aquatic and flying forms. This gets in all three subclasses and all three locomotor types, rather than focusing only on Old World placentals. —Preceding unsigned comment added by Kjaer (talkcontribs) 23:36, 25 November 2008 (UTC)

Why are all four of the mammals in the taxobox composite image part of Laurasiatheria, one of only four major groupings of placental mammals? The image may represent diverse forms of mammals, but it doesn't represent their taxonomic diversity. This composite should be moved to the Laurasiatheria article, and a new one should be created that includes perhaps a marsupial and at least one charismatic member of another of the four main placental groups. Perhaps a lemur would be nice? deranged bulbasaur 16:18, 15 June 2009 (UTC)

It would also be nice to include other kinds of diversity to get a sense of the widely-distributed fauna. All four of these animals are from the Old World, and all four are land-based. Discrimination, I tell you! deranged bulbasaur 16:29, 15 June 2009 (UTC)
I've discovered a copyright issue with the image as well, so I listed it for deletion at commons. deranged bulbasaur 17:37, 15 June 2009 (UTC)
I don't think we have to show the really rare types like monotremes. I say we have one hoofed, one small and furry, one aquatic, and one large carnivore. Or maybe bump it up to six by adding a bat and a primate. Or up to eight by adding a marsupial and a monotreme. —Preceding unsigned comment added by (talk) 05:14, 9 February 2010 (UTC)
I think four mammals is sufficient, but I agree that the current range is unsatisfactory. I would advocate keeping the bat and any one of the others, and adding a cetacean and a marsupial. (Monotremes are such a small group that I think we can safely ignore them without seeming unrepresentative.) To meet the preferences of the anonymous user above, (one ungulate, one small/furry, one aquatic, one large carnivore), perhaps the giraffe could be the other that remains, a killer whale could replace the lion, and a wallaby could replace the hedgehog. -Agur bar Jacé (talk) 17:00, 26 January 2011 (UTC)

Okay, now we have the opposite problem. It should not take eighteen separate images to give an idea of the concept "mammal". Six, maybe, but not eighteen. -Agur bar Jacé (talk) 20:49, 24 April 2011 (UTC)


The locomotion section of this article contains almost no information or contents. It only contains a few links to other article. Either this section should be deleted, or information should be added to summarize the contents of the linked articles. KnowledgeRequire (talk) 22:28, 27 August 2009 (UTC)


I added reference template to this article because of its lack of reference and citations. The beginning sections of this article do not contain any citations at all. Please fix this issue. KnowledgeRequire (talk) 22:39, 27 August 2009 (UTC)

Domain Eukaryota[edit]

Enough. No more edit wars. Eukaryota ISN'T REQUIRED. Anyone wanting to find out about Eukaryotes will ardly have this article as their starting point. (talk) 15:19, 12 February 2010 (UTC)

Not a valid argument. The reason for Eukaryota being there isn't that someone necessarily wants to find out about eukaryotes starting from the mammal article, but that someone wanting to find out about mammals might be interested in the fact that they are eukaryotes. Just as for animals, vertebrates, etc. And, going by your edit summary on this edit I think you're the one doing the edit warring. -- Why Not A Duck 21:22, 12 February 2010 (UTC)
It takes two to editwar. I don't know at how many pages this has been going on, but I've removed it from this one per the guideline at Template:Taxobox#Classification. We don't include all taxa that could possibly be included in the taxobox, even though people may also be interested in reading that mammals are members of Neomura, Opisthokonta, Metazoa, Bilateria, Deuterostoma, Craniata, Osteichthyes, Actinopterygii, and a couple of other taxa. Ucucha 21:29, 12 February 2010 (UTC)
That is right. All the text you put down is absolutely ridiculous, and shouldn't be in an infobox. (talk) 05:40, 16 February 2010 (UTC)
This is complex, and we'll have similar issues at all level of the Tree of Life. In fact I suggest Wikipedia_talk:WikiProject_Tree_of_life should the central discussion place, and that all lower-levels should be notified - only the one level down, they can notified further WikiProjects; unless the one level down is dormant, in which case we look one more down level down.
We should not have any further unilateral edits and no more uncivils comments or editing summaries. --08:00, 16 February 2010 (UTC)
The rest of my suggestions are much more tentative, and I suspect discussions will involve examples of all levels of the Tree of Life.
  • WP will need some general rules that working of all levels of the Tree of Life.
  • I suggest we need some sort of "sliding scale" . In words, the classifications should work up N levels from an article, and also lower a few levels for intermediate taxa - e.g. Arthropod could go up to Bilateria and Metazoa and down (all at similar levels) to Chelicerata, Myriapoda, Crustacea and Hexapoda.
  • To avoid confusing readers (and editors :-D), where possibly we should avoid names that are controversial or have only recently been consensus in the literature. However, we can't always the cases, for example the descendants of Arthropod are debated. And Tetrapod is not clearly defined, but I'd included it because the transition from "fish" to land is too important.
  • If we go for a "sliding scale", it needs to be slighty "sticky". For example articles at N level and N+1 should use the same scale, otherwise readers (and editors :-D) will be confused because they'll have a new and unfamiliar set of "signposts" at each level. This implies that the "signposts" will be every 2 or 3 clades in a cladogram or every few levels in a Linnean taxonomy. Then the articles about the "signpost" taxa will have fill in the intermediate taxa.
  • I think that means that the articles about the "signpost" taxa would longer taxoboxes that those of other taxa. --Philcha (talk) 08:00, 16 February 2010 (UTC)

Fossil range[edit]

Reverted edit by (talk · contribs) that changed {{Fossil range|220|0}} to {{Fossil range|230|0}} as no clear evidence for this change. Article text says "The first true mammals appeared in the Late Triassic (ca. 200 million years ago)" so the fossil range should strictly agree with this and be {{Fossil range|200|0}}. (talk · contribs) please provide evidence for such a change --Senra (talk) 20:27, 22 July 2010 (UTC)

This is a matter of definition, perhaps. The oldest mammals listed in McKenna and Bell's Classification of Mammals (1997) are Kuehneotherium and Woutersia from the late Triassic, about 230–200 mya. Morganucodontids, haramiyidans, and Adelobasileus also lived in the late Triassic, but McKenna and Bell did not consider them to be mammals. They follow Rowe's definition of "mammals" as the crown group that includes all living mammals, their most recent common ancestor, and all its descendants. Thus, what is or is not a mammal depends on the relationships envisioned among the early mammals. According to this study by Zhe-Xi Luo and colleagues, Kuehneotherium is not, in fact, a crown-group mammal, and the earliest mammal may not have appeared until the middle Jurassic. If Rowe's definition is followed, that is, because Luo and colleagues in fact use a more inclusive, and stable, definition of "mammal" that includes the last common ancestor of Sinoconodon and living mammals and all its descendants, which would indeed place the earliest mammals in the late Triassic.
Exactly how old the oldest mammal is depends on the precise age of these late Triassic possible mammals; I don't know these ages, although our article on Sinoconodon says it is 208 million years old (without a reference). But to summarize—The age of the oldest mammal depends on your definition of "mammal" and your hypothesis about the relationships among early mammals and not-quite-mammals. Ucucha 21:09, 22 July 2010 (UTC)
Going to be honest here. I am not qualified to understand this subject never mind discuss it. Neverthless, as an encyclopaedia article, I would feel happier if the text qualified when the first true mammal appeared with a reliable reference (WP:RS), and the {{Taxobox|fossil range=}} parameter should then be the same time --Senra (talk) 21:29, 22 July 2010 (UTC)

is this correct?[edit]

at the beginning of the article, it says:

"Some mammals have sweat glands, but most do not."

Yet when you go to the sweat glands article, it says:

"Sweat glands, or sudoriferous glands, are exocrine glands found under the skin in all mammal species"

So one says most don't have sweat glands. While the other one says all have sweat glands. I'm not a biologist, so I have no idea which one is right. (talk) 23:39, 10 October 2010 (UTC)

Good catch. I wish I knew which one is true. A few minutes of research on the web seem to indicate that most mammals do have sweat glands, though not necessarily all over their body like humans do; but that maybe some (whales, elephants, hippos) do not. The person who made this edit ([6]) didn't make any other edits or make any comments, so we really don't know what their source is.
So: Does anybody have a good source for this information? Something that meets WP:RS and will support an assertion that mammals always, usually, or sometimes have sweat glands? I took a few minutes to look around and didn't find one. -- Why Not A Duck 19:28, 11 October 2010 (UTC)
Here are some sources on the topic: [7],[8], and of course milk production comes from glands that are modified sweet glands [9] Hardyplants (talk) 22:04, 11 October 2010 (UTC)

Social structure?[edit]

So, I couldn't help but notice that the "Social Structure" header is a blank section. I assumed this was vandalism at first, but going back, it has apparently been blank for a year and a half. The section was blanked for a copy vio from Britannica, and never updated. I find it hard to believe that I'm the first person to notice this, but well, there you go. I think the solutions would be to rewrite and cite, or just remove the empty header altogether. Thoughts? Tossrock (talk) 22:43, 11 November 2010 (UTC)

Well, late as it is, I have a thought or two (about the limits of my thinking). Social structure is in my view the most important topic in the article. As it is a long one it should be offloaded to another article, "Mammalian social structure" or similar. For the header, well, it should stay to indicate what the article needs. We should not be interested in artcles with no content just because no one volunteers to develop the content. That is the responsibility of the public. WP should not be in the position of pretending it was done. For the copying - no, never do that. What good is that? If I want to see what Britannica says I go to Britannica, not WP. I fact I would go so far as to say WP spin-offs of Britannica articles are just trash getting between me and my reading of Britannica. You can't create an encyclopedia overnight, regardless of how sanguine our intents when we began. We need the markers to tell us where we should work.Dave (talk) 22:30, 19 April 2011 (UTC)

Largest order[edit]

The article states that largeness is measured by biomass. I do not believe that is so. Biomass is the average weight of the individual multiplied by the density. No such figures have been collected globally for mammals. I can find no source for that. What I do find is that the order of orders given - Rodentia, Chiroptera, etc. - is actually the order by number of species given in a few major sources. This figure is what some sources have been calling the diversity. One might intuitively suppose that the greater diversities imply the greater biomasses. A biomass is the estimated sum of the weights of all the individuals of the species. If there are more species you might expect a greater weight of individuals. This hypothesis would have to be prooved. There is nothing at all about it either in this article or in the sources I can find on the Internet. So, I am going to change the presentation of that concept slightly to mean the diversity (number of species). If anyone has sources showing that biomass was actually what was meant, now is the time for them.Dave (talk) 07:55, 21 April 2011 (UTC)

Mammal classification revisited[edit]

What a Gordian knot this topic is. I doubt if anyone is prepared to accept the proposed "solution" given in Mammal classification. Few people certainly are following it and no one is enforcing it. I don't like it because it is a mixed bag. No one has that classification. One recent commentator noted that WP should not be trying to legislate classification. If any agency can do that it must be the ICBN. I can't seem to find anything higher than genus. Maybe it is detailed in the full code but that is far too expensive for the likes of me and they aren't giving that away for free. For their price it is among the rare book items. In any case until we find out better we need to solve some of these contradictions. The families are well-legislated and that Mammalia is a class is not disputed. The main problem here seems to focus of the marsupials. Exactly what are they, an order, an infraclass or an informal category? In this article we get two contradictory points of view. The first is in the intro and it talks about the infraclass Marsupialia. The second in in the box and it talks about the infraclass Metatheria. Well, you can't have it both ways. I will ignore the fact that all books I can can find published in 2011 call Marsupialia an order. I don't want to strain WP. I'm against changing all the orders to suborders, only to end up with not enough categories to take care of it. So far no one of sufficient objectivity has come forward with a WP solution. Mammalian classification is a good article, I think, until it starts talking about what all WP is or is not going to do. The editors do not have that power. What I want to do is this. First, let's make it consistent. I go for the box. I like Metatheria and Eutheria. The name is more systematic. That leaves Marsupialia with no place to reside if we follow our main source, Mammal Species of the World, which never even heard of the marsupials although it lists orders at some time or other under the marsupials. Fine. What is the good of citing sources if you are not going to follow them? But, we cannot ignore the variation. Therefore I propose to describe the problem most briefly in the intro with some explanation of why the boxes and write-ups of other taxa differ from this one. We want to present system with alternative systems, we do want want to present chaos. This is how it seems to me at this moment after some hours of investigation.Dave (talk) 14:37, 21 April 2011 (UTC)

It's OK. Someone else changed it a bit. It boils down to a question of English. Out language does not have quite that freedom of word order so I'm putting it in straightforward declarative English.Dave (talk) 15:00, 21 April 2011 (UTC)
The ICZN (let alone the ICBN) has no bearing on questions like this at all; it deals only with nomenclature, not with classification. There are indeed different treatments (though I doubt any scientist who knows about mammal systematics will still classify Marsupialia as an order). Ucucha 15:33, 21 April 2011 (UTC)
Thanks. I recognize your opinion but I do think the ICZN has to consider classification to some degree. I'm mainly concerned with the public knowing the relative value of this material. Most of it is unsourced and I note it is very condensed, which may be par for scientific communication but is not so for the public. I'm mainly going to be looking slowly at sources, and for inconsistencies and confusions. At the end I hope we can get that tag off. A classification as a good article is not too much to hope for, even. Correct me whenever you please. If that in turn should need correction I will bring it up. I work very slowly. I have a few other irons in the fire. I sort of concluded a slow pace in these thing is a virtue.Dave (talk) 16:12, 21 April 2011 (UTC)


Thanks for your responses to my initial corrections. A topic as large as this certainly can't be the work of one man and there are many points of view. Feel free to correct away. Actually I have no firm idea of what should go in here. I noticed the tag at the top and lack of attention to refs. And, I noticed the inconsistencies and some errors. No big deal. I make errors all the time; furthermore, whatever way anyone wants to write or arrange it is fine with me. I expect to get corrected often here. I don't see how it could be any different for such a general topic. But, there are some things I would like to focus on. If you are going to say something significant please reference it it properly; I will be looking at that. Please don't copy. Have a thought for consistency - don't leave us hanging with two contradictory assertions. If other articles contradict what we say, try to to give the reader some idea why. If you are giving us information, say where you got it. Don't guess. Make sure the ideas you are putting in are accurately represented. Give the reader enough information to understand what you are saying. If necessary use the blue links. I regard this as at the end-user level not the condensed scientific version. We want to explain, we don't want to impress or appear "smart." Please write in good English. So, that's my mission. Do it your way, or keep it your way, but simply, accurately, consistently and in good English. I don't know where the end of the road is but I hope in a good article recommendation.Dave (talk) 20:25, 21 April 2011 (UTC)

main image[edit]

Let me make this perfectly clear. Brezhnev and Nixon are notable dead people on two sides of the cold war. Whatever your personal opinion of each, they represented the two great axes of the last century, and each is dead, and their picture is licensed. Replacing this with an unlicensed vanity shot of an "American Male" (!) in the name of "neutrality" is a fail on many levels, including WP:NONFREE and wp:3rr. Get a neutral, licensed picture and consensus before you revert. μηδείς (talk) 23:39, 3 July 2011 (UTC)

For future reference in case of trouble regarding this matter see which resulted in the blocks of three users. μηδείς (talk) 00:51, 4 July 2011 (UTC)
Apart from the other failings of the user(s) pushing for this image, I agree with you that the concern about neutrality makes little sense. About as little, in fact, as saying that the image is non-neutral because it discriminates against echidnas because it shows only a platypus. Ucucha 00:58, 4 July 2011 (UTC)
Exactly, they are notable dead people from the cold war era. They are not notable mammals. Considering the short time frame of the cold war (a few decades), compared to the time mammals have been around (millions of years), I think that image is increasingly pointless. Surely on the entirety of the internet, there is a more neutral image of a human. If a human need be represented at all. Why not replace it with a close evolutionary relative, say a gorilla or a chimpansee. Everyone's happy. Just an idea. Vince (talk) 10:52, 28 October 2011 (UTC)

Hello, putting Nixon and Brezhnev doesn't describe correctly humans as mammals. it should be a naked male and female from different races. Thank you -- (talk) 00:53, 26 May 2013 (UTC)

I'm not sure about Nixon and Brezhnev either. Mostly in that as I'm on team human, I'd rather we send in our stars to all-start team, not our fourth line. mattclare (talk) 02:43, 25 May 2015 (UTC)

whales not mammal[edit]

whales are not mammal they are fish — Preceding unsigned comment added by (talk) 07:25, 11 July 2011 (UTC)

I do hope you are joking good sir. (talk) 15:49, 12 September 2011 (UTC)

List of Mammals[edit]

I removed the section called 'List of Mammals since, though it was nicely formatted, such lists belong at List of mammals and its subpages. There isn't room to list all Mammals on this page and while there should be some examples mentioned a (very incomplete) list doesn't really help. Eluchil404 (talk) 03:41, 21 October 2011 (UTC)

First appearance of mammals and mammaliaforms[edit]

According to the section True mammals evolve in the Triassic,

The first true mammals appeared in the Late Triassic (ca. 200 million years ago), over 70 million years after the first therapsids and approximately 30 million years after the first mammaliaforms.

This is, at best, unclear.

Was Adelobasileus a "true mammal"? Apparently not, as it appeared 225 million years ago according to T. S. Kemp, The Origin and Evolution of Mammals, 2005, p.138. The claim is surely not that "mammaliaforms" appeared 30 million years before that, in the Permian. Is Adelobasileus then the first mammaliaform, in the sense intended? That interpretation creates a problem on the other end, since it locates the origin of "true mammals" in the Jurassic, contrary to what is asserted. Perhaps the term "mammaliaform" is being applied to animals living even earlier, Probainognathus for example?

What is a true mammal?[edit]

However that is resolved, "true mammals" needs to be made clear. What is this group that appeared in the Triassic, 30 million years after the mammaliaforms (however defined)? It cannot be the crown group mammals, since (according to the diagram in Luo et al. 2011) they did not appear until around the base of the Pliensbachian, well into the Jurassic. No other candidate is obvious, however.

Peter M. Brown (talk) 23:39, 9 February 2012 (UTC)

Song Lyrics in Opening Paragraph[edit]

The end of the third sentence in this article, "red blood cells lacking nuclei and a large four-chambered heart maintaining the very high metabolism rate they have," is from a They Might Be Giants song. Inwikiveritas (talk) 06:30, 16 February 2012 (UTC)

I listened to Apollo 18 today and it turns out this phrase wasn't lifted verbatim from Mammal but it is very close. Only two words were changed - a preposition was swapped out for a conjunction and a definite article became an indefinite article, so "red blood cells lacking nuclei through the..." from the song became "red blood cells lacking nuclei and a..." in this article. This seems like it would be a copyright issue to me, though I don't really know anything about that.
I suggest that one of the many helpful, competent editors on this site make the appropriate changes to the article. I'd do it myself, but I'm hardly qualified. I'm just a random TMBG fan who wanted to find out something about mammals and found something fishy instead. Inwikiveritas (talk) 01:01, 17 February 2012 (UTC)
Well, I like to think of myself as a helpful and competent editor, but I'm not sure what "appropriate changes" you have in mind. The song could certainly be noted in an "In popular culture" section such as many articles have, but creating such a section for the Mammal article would be a huge undertaking, one I'm not prepared to volunteer for. Are you suggesting merely that a link be provided, in the External links section, to one of the performances of Mammal that are available online? That would not be hard. Peter M. Brown (talk) 20:08, 4 March 2012 (UTC)
I failed to clearly make my point. I do not believe any external links are needed and I certainly do not think an "In popular culture" section should be added; as popular culture is itself a construct of one species of mammal, this would undoubtedly be a huge undertaking, as Mr. Brown noted.
My intent was to point out that this article contains information from an uncited source and that part of this information is a direct quote, though it is not presented as such. Upon further reflection, I think that TMBG's Mammal is an entirely inappropriate source for this article. While the information may be accurate, the Johns are entertainers, not biologists. Surely an article on mammals should be based upon more reliable sources. Inwikiveritas (talk) 17:01, 13 May 2012 (UTC)

Elephant teeth[edit]

Andy Dingley has added a note to the effect that elephants are an exception to the rule that, in modern mammals, teeth are replaced either once or not at all. This is not the case.

An elephant has only six molars per quadrant, not present all at once, that erupt in the rear, move forward as the animal ages, and are shed in front. Since no molar appears in the location where a tooth is lost, one could say that the teeth are not replaced at all—each molar enters on cue, plays its assigned part while marching forward in the mouth, and exits the stage as the script dictates. Alternatively, one could say that molars 4, 5, and 6 replace molars 1, 2, and 3. Either way, elephant teeth are replaced at most once.

Peter M. Brown (talk) 17:16, 4 March 2012 (UTC)

I'm no expert on elephant teeth, so please either undo my change or else clarify it according to your explanation here. All I know is that elephant's teeth don't obviously follow the simple replacement scheme as previously described. The previous description, as stated was unclear. Whether this is because elephants are (as I thought) one of the exceptions, or whether (as you describe here) they're both "replaced at most once", yet in a manner that's more complex than for other mammals, I can't say. Either way, readers are likely to benefit from clarification.
I'd also appreciate it if someone could perhaps expand the "in toothed whales and murid rodents" exception note to describe what the difference is with the whales. Also where do the lagomorphs fit into this? It's not all of Glires that have continuously-growing teeth is it? Andy Dingley (talk) 01:14, 5 March 2012 (UTC)
All Glires have continuously growing incisors; only some (e.g., some voles) have continuously growing cheekteeth too. What that note probably refers to is the fact that living muroid rodents have no premolars; they have a single set of molars that is not replaced. However, these molars are normally rooted and have finite lifespans. Ucucha (talk) 13:18, 5 March 2012 (UTC)

No consensus[edit]

According to a recent edit, there is consensus that Mammalia should be defined as the crown group containing the montremes (sic) and the metatherians. Consensus means general agreement, however, which is wholly lacking in this case. To be sure, Rogier, Wible and Hopson, cited in the Evolutionary History section of the article, do adhere to this definition, as do McKenna and Bell (also cited). However, in the important recent compendium by Kielan-Jaworowska, Cifelli, and Luo—cited as well—the docodonts, the morganucodonts, and Sinoconodon—none of them crown mammals—are specifically included. Mammalia is widely used in this sense; Yaoming Hu et al. (2010) consider Sinoconodon and the morganucodonts to be mammals while Martin et al. (2010) so classify the docodonts. In saying that Brasilodon is the sister of Mammalia and younger than many mammals, Jun Liu (2010) and his co-authors are not proposing the radical thesis that this genus is more closely related to extant mammals than are the docodonts; rather, they simply and justifiably take for granted that their readers will understand "mammal" in a broad sense.

Rowe (1988) both introduced the term "Mammaliaformes" and promoted the crown-group definition of "Mammalia". Use of the former term has become widespread. These are two different terms, however. Using the former does not imply agreement with Rowe's argument that the latter should be restricted to the crown group.

I have accordingly deleted the sentence involved. There is adequate treatment elsewhere in the article of the fact that some writers do limit Mammalia to the crown group and the fact that this limitation excludes mammaliaforms that qualify under the traditional trait-based classifications.

Peter M. Brown (talk) 15:04, 28 March 2012 (UTC)

Image use[edit]

Several of the images in Mammal seem to be provided just for decoration. I refer particularly to

Though the animals depicted are mammals, they have no special relevance to the sections with which they are associated. Rather than clarifying or illustrating the information in the text, they are distracting. Representations of Neogene animals are not helpful to someone reading about the first appearance of mammals or of their distinctive features in the Mesozoic, nor are photographs of primate skeletons, cheetahs, or bats at all enlightening in connection with a discussion of animal intelligence. By way of contrast, each of the eighteen images in the Reptile article relates directly to the text and aids readers' understanding. These Mammal images, on the contrary, are clutter.

Wikipedia:Images#Pertinence and encyclopedic nature does discourage the removal of images. In this case, however, they detract. Is there an argument for retaining them?

Peter M. Brown (talk) 17:00, 5 April 2012 (UTC)

I agree. Images should illustrate or support the text, not decorate it. MMartyniuk (talk) 17:31, 5 April 2012 (UTC)

Prototherian/therian split "abandoned"?[edit]

"The division of prototherians versus therians, however, has now been abandoned among professional paleontologists."

That's an extremely strong statement, and completely dissonant with the rest of the article, which presents such a division both in the context of the "traditional" taxonomy, and McKenna/Bell. Can someone with ready access to the source cited please clarify what precisely it says on this matter, and whether it really represents the consensus view of "professional paleontologists"? (talk) 22:18, 16 April 2012 (UTC)

McKenna and Bell used Prototheria for a narrow taxon that includes only the monotremes. I think is true that no paleontologists now divide early mammals into two distinct groups of prototherians and therians; instead they recognize a large number of approximately order-level groups among the Mesozoic fauna (see e.g. Kielan-Jaworowska et al.'s Mammals from the Age of Dinosaurs). Ucucha (talk) 22:40, 16 April 2012 (UTC)
Yes, but is correct that the statement is a strong one; as such, it requires a secondary source. In making the claim, I thought that I had one—specifically Kielan-Jaworowska et al. 2004—but I cannot now find such a statement in their book. They seem only to say (p. 207) that they are abandoning it. I could say that Prototheria is now known to be a paraphyletic taxon; for that I can cite Luo; et al. (2002). "In quest for a phylogeny of Mesozoic mammals". Acta Palaeontologica Polonica. 47 (1): 1–78.  Unknown parameter |separator= ignored (help) I'd prefer, though, to make a generalization about current usage among paleontologists. Peter M. Brown (talk) 00:29, 17 April 2012 (UTC)
Whether Prototheria is paraphyletic depends on how it's defined. Both Simpson (1945) and McKenna and Bell (1997) included only the monotremes in it, an unquestionably monophyletic group. Rose, K.D. (2006). The Beginning of the Age of Mammals. The Johns Hopkins University Press.  has some discussion relevant specifically to this topic (p. 49). The discussion is too long to reproduce here, but "Supposed differences in braincase construction that were the basis of the dichotomy between nontherian and therian mammals are now known to be inaccurate, and this bipartite division of Mammalia has been largely abandoned (Kielan-Jaworowska, 1992)." is a useful quote. Ucucha (talk) 01:13, 17 April 2012 (UTC)
Thanks for the replies, this is somewhat clearer now. So the gist of is, that it's not clear whether/which of the two various Mesozoic mammals fall into? Can we make this somewhat more clear in a way that's accurate with respect to the source? As it stands it reads like it's offering a rebuttal to the taxonomies as presented, rather than offering a caveat to their application to clades not enumerated therein. At least to my possibly somewhat befuddled initial reading. (talk) 01:29, 17 April 2012 (UTC)
I have deleted the subsection. Except when it is clear that intellectual history is being presented, there is no need for Wikipedia articles to present outdated views. The fact that the classification in the following section pairs Prototheria with Theriiformes, not with Theria, can only confuse the reader. Peter M. Brown (talk) 03:37, 17 April 2012 (UTC)
A somewhat Gordian solutions, but it works for me. I've tried to fix up the infobox to follow along. It's still not ideal, because this ends up pointing to various articles that are actually located at different names, make contradictory statements about the ranks of these taxons, etc. If McKenna/Bell is the current state of the art, though, maybe those others will conform in time. (talk) 00:18, 19 April 2012 (UTC)
It's not, though, and the confusing state of Wikipedia articles about basal mammal classification represents real confusion in the literature. I'm unhappy that the infobox now calls Marsupialia and Placentalia "cohorts"; no one except for McKenna and Bell those few who slavishly follow them uses those ranks for the marsupials and placentals (see, e.g., [10]). Ucucha (talk) 12:26, 19 April 2012 (UTC)
My fault that, I suppose, trying to make it consistent with PMB's "Subclass Theriiformes" edit. WP's own article calls Marsupialia an infraclass, and is more-or-less silent on the rank of Placentalia, in the Eutheria article that it's an alt-title of. So, it seems that we're doing an excellent job of replicating said confusion, if nothing else. Possibly we should keep the same clades in the infobox, but remain silent on their ranks, or else explicitly hedge more, and discuss in the article? (talk) 20:52, 19 April 2012 (UTC)
In this edit, I refer to Theria as a subclass, following the Theria article, and to Placentalia and Marsupialia as infraclasses, following the Marsupial article. If you two want to change my rank assignments, go right ahead. I do agree with Ucucha that calling Placentalia and Marsupialia cohorts does sound odd, but I will not object. Peter M. Brown (talk) 18:00, 20 April 2012 (UTC)
Trouble is, there's a serious problem with referring to both Theria and Theriiformes as subclasses, but with one nested in the other. In fact, two pretty serious problems: firstly, it's a logical contradiction, and secondly, because it's combining information from different sources in a way that doesn't accurately represent either set. So if we're going to have Theriiformes in the infobox, I don't see what else those can be except supercohorts, following the source that uses Theriiformes in the first place. Perhaps we should just skip that 'node' for purposes of the infobox. Or can we include it as an unranked clade? (talk) 06:22, 21 April 2012 (UTC)
Done. Nobody can dispute that, whatever else it is, Theriiformes is a clade. Peter M. Brown (talk) 15:03, 21 April 2012 (UTC)
I'm content with that. It seems like about the best that can be done given the conflict in the sources, without making the infobox a complete dog's dinner. (talk) 03:03, 23 April 2012 (UTC)

recent IP edits[edit]

There have been a large number of recent edits made without talk page discussion, with effects such as removing reference to extinct mammal groups, providing an excessive number of examples of various concepts, and overlinking in the extreme. The edits, while apparently in good faith, are of dubious value, and the IP user has been invited to discuss the edits before continuing, and warned of the possible consequences. μηδείς (talk) 05:06, 12 July 2012 (UTC)


I'm trying to fix this taxobox. Currently, it lists:

Kingdom: Animalia
Phylum: Chordata
Superclass: Tetrapoda
Clade: Amniota
Class: Synapsida
Class: Mammalia

I'm assuming we don't want Synapsida in there (ie 2 classes) and I'm wondering if we want the most immediate parent of Mammalia there, like we do with eg. a species taxobox when there's a subspecies. Wikipedia:Taxobox_usage suggests: "Taxoboxes should include all major ranks above the taxon described in the article, plus minor ranks that are important to understanding the classification of the taxon described in the article, or which are discussed in the article. Other minor ranks should be omitted." A lot of times we just put the most immediate parent in the taxobox, or perhaps all the minor parents in between this taxon and the next higher-ranked "major" rank. We can't really do that here, I think, since there is a lot of crap between Mammalia and Chordata.

I'm trying to start some discussion about this at Template_talk:Taxonomy/Mammalia, but that might focus more on implementation, so it might make sense to focus here on what exactly should the taxobox look like here. Perhaps:

Kingdom: Animalia
Phylum: Chordata
Node: Mammaliaformes
Class: Mammalia

or just Mammaliaformes-Chordata-Animalia? Leave it like it is? ErikHaugen (talk | contribs) 18:34, 28 November 2012 (UTC)

Neutrality is incompatible with considering Mammalia as subordinate to Mammaliaformes.
See my argument at " Talk:Mammaliaformes#By Rowe’s definition, Adelobasileus and Sinoconodon are not mammaliaforms", which engendered no discussion. I referred mainly to Rowe's 1988 definition, but I pointed out that the exclusion is also implied in a 2011 article by Rowe and Luo and that Adelobasileus is explicitly ruled out of Mammaliaformes in a 2005 article by Bonaparte et al. Though not a mammaliaform, Adelobasileus is a widely considered a mammal, as in the Wikipedia Adelobasileus article. See also the discussion in the Mammaliaformes lead.
Mammalia can usefully be presented as subordinate to Synapsida (a class), Therapsida (an order), Eucynodontia (an infraorder), or Chiniquodontoidea (a superfamily); other possibilities are the unranked taxa Cynodontia, Probainognathia, and Mammaliamorpha. In taxoboxes, it is not productive to try to preserve the Linnaean rank hierarchy.
Peter Brown (talk) 23:50, 28 November 2012 (UTC)
Why not simply change Synapsida, Therapsida etc. to clades (which is how they're treated in a lot of published literature) and save the non-ICZN ranks for extant clades, rather than grades? This seems to have worked for Bird wrt Dinosauria. MMartyniuk (talk) 19:21, 29 November 2012 (UTC)
"Save the non-ICZN ranks for extant clades"? Please clarify. All the relevant clades are extant; living members of Mammalia are also members of every more inclusive group. And by "non-ICZN ranks" are you thinking of levels like branch, series, and cohort? Peter Brown (talk) 14:23, 30 November 2012 (UTC)


From what I know they are the only animal class to give live birth whilst the others lay eggs, correct me if I am wrong but I think this should be on the page (talk) 19:26, 30 September 2013 (UTC)

Some mammals (humans) give live birth, others (echidnas) don't. Some reptiles (southern water skinks) give live birth, others (turtles) don't. All one can say is that most mammals give live birth while most reptiles don't. There are exceptions both ways. Peter Brown (talk) 21:31, 30 September 2013 (UTC)

Locomotion section[edit]

I feel the locomotion section could be reformatted or consolidated. At the very least, the individual locomotion modes could be indented more, to separate them from "Feeding" (I guess there is a small change in font size, but it is not readily apparent. Rather than have empty redirects or snippets, why not just list it something like below? Animalparty (talk) 00:10, 16 October 2013 (UTC)


Mammals evolved from four-legged ancestors. They use their limbs to walk, climb, swim, or fly. Some land mammals have toes that produce claws for climbing or hooves for running. Aquatic mammals like whales and dolphins have flippers which evolved from legs.

Is this statement correct in relation to evolutionary science?[edit]

The article states the following

Mammals took over the medium- to large-sized ecological niches in the Cenozoic, after the Cretaceous–Paleogene extinction event emptied ecological space once filled by reptiles.[25] Then mammals diversified very quickly; both birds and mammals show an exponential rise in diversity.[25] For example, the earliest known bat dates from about 50 million years ago, only 16 million years after the extinction of the dinosaurs

I didn't think that's how evolution works. Species 'evolve' regardless of whether other species are already in a particular niche.

Montalban (talk) 21:21, 17 October 2013 (UTC)

That's controversial and not the position of the cited source. Have you another (well-sourced) explanation for the explosive diversification of mammals after the demise of the non-avian dinosaurs? If so, please contribute it to the article as an alternative view. Peter Brown (talk) 22:10, 17 October 2013 (UTC)
I think the issue might be over the wording "took over", which is somewhat semantic. There is a great deal of evidence and associated theory that large adaptive radiations or niche transitions often (but not always) occur after extinction events, whereby reduced competition allows more rapid establishment. Evolution and/or natural selection is always occurring, but large scale adaptive radiations show patterns. Animalparty (talk) 20:18, 18 October 2013 (UTC)
Since the boundaries of ecological niches shift with time, "took over" isn't quite right; it does suggest that a niche was vacated and then re-occupied by a different taxon. Whether there is really such a thing as a vacant niche is controversial at best. Certainly, though, a taxon's occupation of a niche does inhibit the evolution of a new taxon that needs a very similar niche. Niche occupation does influence evolution. Peter Brown (talk) 21:59, 18 October 2013 (UTC)

Peter Brown, I'm not sure about your point, and then your question because I cited what is said in the article. Montalban (talk) 12:57, 1 November 2013 (UTC)

Sorry if I was confusing. The passage you quote presents an explanation of the explosive diversification of birds and mammals in the early Cenozoic. I interpreted you as disagreeing with this explanation. If you have an alternative explanation for the rapid diversification, supported by a reliable source, you are welcome to include it in the article as a competing opinion. Otherwise, you will have to let the text stand as it is. There is a bit of a problem with the phrase "took over" but I don't think it relevant to your concern. Peter Brown (talk) 22:20, 1 November 2013 (UTC)

I think there is a problem with that paragraph. I would follow Peter Brown advice, but the "took over" phrase is problematic, and besides, for most of the Eocene until the Eocene extinction, birds dominated most of the higher ecological niches, not mammals. Mammals were mostly tiny crawling critters, with a few exceptions in Australia and in the ocean. Gug01 (talk) 17:46, 30 December 2014 (UTC) Gug 01

Removal of incorrect information[edit]

I have removed the claim that [mammals have hair] "With some exceptions, including elephants, hippopotami, babirusas, armadillos, pangolins, naked mole rats and the majority of marine mammals" on the grounds that it is false. My reasoning is as follows:

  • Elephants, armadillos, pangolins, babirusas (or at least of some of them), and naked mole rats all have hair
  • Hippopotami, while very nearly hairless, also have hair
  • While it is technically true that most marine mammals are hairless, all of the ones that are are cetaceans (i.e. all non-cetacean marine mammals have hair, including, as it happens, the single hairiest animal on the planet), and there even are a few cetaceans that do have hair, so I think the rephrasing I have used is more accurate.
Anaxial (talk) 17:57, 2 October 2014 (UTC)
I see that we posted more or less simultaneously. Anyway, to reply to your question, they aren't considered hairless because they're not. It really is as simple as that. I can link to some pictures if you're not convinced? Anaxial (talk) 17:59, 2 October 2014 (UTC)
Ok, I've removed the duplicate post above. Brandmeistertalk 18:13, 2 October 2014 (UTC)


The articles creates the false impression that monotremes are the only mammals with a cloaca, when this is also found in other mammals, such as tenrecs, golden moles and certain shrews. (talk) 22:57, 6 November 2014 (UTC)

Lede too complicated[edit]

The first paragraph of an article this critical to science should be understandable to an eight grader. It is way too complicated currently. Endothermic amniote?? I'm a doctor and have to think about that one. Gaff (talk) 06:17, 19 December 2014 (UTC)

After reading your sentence I realized I didn't really know what an amniote was. Unfortunately the lede to that article is easily twice as confusing as this one! Beach drifter (talk) 07:11, 19 December 2014 (UTC)
I agree with User:Beach drifter! Way to complicated. Gaff, could you please simplify the lead? Gug01 (talk) 17:48, 30 December 2014 (UTC) Gug 01

New Project?[edit]

I for one, would find it very interesting to see what the list would look like if we expanded the countdown for our "List of heaviest land mammals" page to 15 or 20. — Preceding unsigned comment added by ZoologyAnon (talkcontribs) 21:32, 9 August 2015 (UTC)

Richard Nixon[edit]

Rio Olympics Boxing Champions as suggested image for humans

There's a photo a used to represent humans on the Mammals page. Is Nixon really the best example of a human? Perhaps we can use a cropped version of the picture in the Humans article. --rathat 00:14, 28 May 2016 (UTC)

wp:BEBOLD--Mr Fink (talk) 00:23, 28 May 2016 (UTC)
"Is Nixon really the best example of a human?" Yes. BrightRoundCircle (talk) 11:12, 8 July 2016 (UTC)
This is a picture of two important world leaders with an interpreter, not a mere picture of Nixon. I don't care if we put up a picture of Mandela, the Dalai Lama, or John Paul II, but we should have actual live humans engaged in a uniquely human activity, not the cartoon image of two generic caucasians from Voyager. μηδείς (talk) 03:21, 26 September 2016 (UTC)
The newly substituted image of several people is quite unclear, the nixon/kruschev image was chosen for clarity and neutrality (and certainly not politics, which are totally irrelevant, and which seems to be the OP's objection above). I intend to reverse it shortly, but will give some time so that an uncluttered immediately recognizable substitute might be offered. μηδείς (talk) 17:03, 30 September 2016 (UTC)
I'll suggest a cropped version of this picture from the 2016 Olympics as visually clear, celebratory, non-political, and racially diverse. File:Medal Ceremonies. Boxing 60 kg.png μηδείς (talk) 18:40, 30 September 2016 (UTC)

External links modified[edit]

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Dunkleosteus77, any particular reason for removing ISSNs from citations? BrightRoundCircle (talk) 19:54, 8 July 2016 (UTC)

To be consistent. Basically all 85 journal refs had an available ISSN, but only 4 of the refs had an ISSN present. So, instead of looking through the other 81 journal refs for ISSN's, I just deleted the 4 that were present.   User:Dunkleosteus77 |push to talk  05:45, 9 July 2016 (UTC)

GA Review[edit]

This review is transcluded from Talk:Mammal/GA1. The edit link for this section can be used to add comments to the review.

Reviewer: Chiswick Chap (talk · contribs) 18:07, 6 September 2016 (UTC)

I'll take this on. Chiswick Chap (talk) 18:07, 6 September 2016 (UTC)

General comments[edit]

This is a fine article and I have few general comments. The writing is exceptionally clear, with fine expositions of some technical subjects, such as "Evolution from amniotes".

On the whole I'm not keen on multiple images for the lead, but the fully-linked array of well-chosen example mammals is interesting and engaging, and might be a model for other "group" articles.

The illustrated cladogram in "Molecular classification" is a model of helpful presentation of technical detail. (I'd love to see part of it in Marine mammal.)

I note the occasional use of "don't" and "can't" in the article. Personally I think these are best avoided, but they, um, don't seem to be problematic in the context.

Specific comments[edit]

  • "it [Simpson's] remained the closest thing to an official classification of mammals." - is a date missing here, or do you mean "remains"? I think one or the other necessary to make sense of the sentence.
I personally didn't write that but I think it refers to the Mckenna/Bell classification   User:Dunkleosteus77 |push to talk  23:37, 6 September 2016 (UTC)
Ok, I've changed it to "-s" accordingly.
  • In the list, whales and ungulates are grouped in the Eparctocyona, but in the cladogram, it's the Cetartiodactyla. What is the relationship of these two clades? Perhaps the two lists could be more closely aligned, or the differences explained.
According to the McKenna/Bell classification, it's Eparctocyona; according to molecular data, it's Cetartiodactyla. That's why they're placed in their respected subsections, and they should remain separate to avoid confusion   User:Dunkleosteus77 |push to talk  23:37, 6 September 2016 (UTC)
Gosh what a nightmare. The article is (therefore) fine, but many other articles are highly confusing on the matter.

(It's a shame that Tikitherium is a redlink, but not an issue for this review.)

  • Could the image caption for Juramaia have an age please.
added   User:Dunkleosteus77 |push to talk  23:37, 6 September 2016 (UTC)
  • The caption and body text starting "Color can be a form of sexual dimorphism..." might be better worded "Sexual dimorphism can involve color differences..." (twice)
The section the image references focuses specifically on coat color, so I think coat color should remain the subject instead of sexual dimorphism   User:Dunkleosteus77 |push to talk  23:37, 6 September 2016 (UTC)
Hm, it makes for tortured English.
  • Coat color can also vary summer to winter.
already there?   User:Dunkleosteus77 |push to talk  23:37, 6 September 2016 (UTC)
Only half. I said "seasonal color change" for the snowshoe hare, which was (obliquely) mentioned.
  • The paragraph about coat color genetics seems weaker than the rest, detracting from the account. Perhaps it can be condensed?
I didn't do much but is it good now?   User:Dunkleosteus77 |push to talk  23:37, 6 September 2016 (UTC)
Already better.
  • "Another mechanism for coat color variation is physiological response purposes" doesn't read well. Perhaps " selection for physiological response"?
fixed   User:Dunkleosteus77 |push to talk  23:37, 6 September 2016 (UTC)
  • The quagga caption should include the date of extinction (19th century).
I put the date when the pictures were taken   User:Dunkleosteus77 |push to talk  23:37, 6 September 2016 (UTC)

I think we're all done. This is a fine article and I'm happy to award it GA status. Chiswick Chap (talk) 08:04, 7 September 2016 (UTC)

Chiswick Chap how do you think the article will stand up at FAC?   User:Dunkleosteus77 |push to talk  22:00, 7 September 2016 (UTC)
Well, I certainly think it's of a good standard. It's a largish article on a 'big' subject that many people may have opinions on, so it could be a substantial push. It has no 'relation with humans' section, which some might consider necessary, it's a matter of opinion. I'd suggest a peer review and a careful polish. Given its size, you might want to put together a small team to take it through. As for how it will stand up, that's in the lap of the gods. Chiswick Chap (talk) 07:31, 8 September 2016 (UTC)


At the time the lead image was made, the caged giant armadillo was perhaps the easiest to see. I would prefer we used the two-toed sloth or the pink fairy armadillo, but am unsure how to format this myself. μηδείς (talk) 03:38, 26 September 2016 (UTC)