Echidna: Difference between revisions
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[[Image:Echidna skeleton.jpg|thumb|Short-beaked echidna skeleton, articulated by [[Skulls Unlimited International]]]] |
[[Image:Echidna skeleton.jpg|thumb|Short-beaked echidna skeleton, articulated by [[Skulls Unlimited International]]]] |
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This used to be the discription section. |
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==Description== |
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Echidnas are small, solitary mammals<ref name=CSIRO06>{{cite book|last=Augee|first=Michael|title=Echidna : extraordinary egg-laying mammal|year=2006|publisher=CSIRO publ.|location=Collingwood|isbn=9780643092044|pages=3|url=http://www.publish.csiro.au/samples/echidna_sample.pdf|edition=[Second ed.]|coauthors=Gooden, Brett, Musser, Anne}}</ref> covered with coarse [[hair]] and [[spine (zoology)|spine]]s. Superficially, they resemble the anteaters of South America and other spiny mammals such as [[hedgehog]]s and [[porcupine]]s. They have snouts which have the functions of both mouth and nose. Their snouts are elongated and slender. Like the platypus, they are equipped with electrosensors, but while the platypus has 40,000 electroreceptors on its bill, the long-billed echidna has only 2,000, and the short-billed echidna, which lives in a drier environment, has no more than 400 located at the tip of its snout.<ref>[http://www.mapoflife.org/topics/topic_41_Electroreception-in-fish-amphibians-and-monotremes/ Electroreception in fish, amphibians and monotremes]</ref> They have very short, strong [[Limb (anatomy)|limb]]s with large [[claw]]s, and are powerful diggers. Echidnas have a tiny [[mouth]] and a toothless [[jaw]]. The echidna feeds by tearing open soft logs, [[anthill]]s and the like, and using its long, sticky [[tongue]], which protrudes from its snout, to collect prey. The [[short-beaked echidna]]'s diet consists largely of ants and termites, while the ''Zaglossus'' species typically eats worms and insect larvae.<ref name=info>[http://www.animalinfo.org/species/zaglbrui.htm Zaglossus bruijni]</ref> |
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The long-beaked echidnas have sharp, tiny spines on their tongues that help capture their prey.<ref name=info/> |
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Echidnas and the platypus are the only egg-laying mammals, known as monotremes. The female lays a single soft-shelled, leathery [[egg (biology)|egg]] 22 days after mating, and deposits it directly into her pouch. Hatching takes place after ten days; the young echidna, called a puggle, then sucks [[milk]] from the [[lactiferous duct|pore]]s of the two [[Mammary gland|milk patches]] (monotremes have no [[nipple]]s) and remains in the pouch for 45 to 55 days,<ref>[http://www.arkive.org/short-beaked-echidna/tachyglossus-aculeatus/biology.html Short-beaked echidna ] Arkive.org</ref> at which time it starts to develop spines. The mother digs a nursery burrow and deposits the puggle, returning every five days to suckle it until it is weaned at seven months. The average wild echidna can grow as old as 16 years.{{Citation needed|date=September 2010}} |
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Male echidnas have a four-headed [[penis]]. During mating, the heads on one side "shut down" and do not grow in size; the other two are used to release semen into the female's two-branched reproductive tract. The heads used are swapped each time the mammal copulates.<ref>{{cite web| author = Shultz, N. | date = 26 October 2007 | url = http://environment.newscientist.com/article.ns?id=dn12838 | title = Exhibitionist spiny anteater reveals bizarre penis | work = [[New Scientist]] [http://www.newscientist.com/home.ns website] | accessdate = 27 October 2006}}</ref> |
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Contrary to previous research, the echidna does enter [[Rapid eye movement (sleep)|REM]] sleep, albeit only when the ambient temperature is around 25°C (77°F). At temperatures of 15°C (59°F) and 28°C (~82°F), REM sleep is suppressed.<ref>{{cite | author = SC Nicol, NA Andersen, NH Phillips, RJ Berger | date = 11 February 2000 | title = The echidna manifests typical characteristics of rapid eye movement sleep | work = [[Neuroscience letters]]}}</ref> |
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==Evolution== |
==Evolution== |
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Revision as of 17:07, 5 December 2011
| Echidnas[1] Temporal range:
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| Western long-beaked echidna | |
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| Family: | Tachyglossidae Gill, 1872
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Genus Tachyglossus | |
Echidnas (/[invalid input: 'icon'][invalid input: 'ɨ']ˈkɪdnə/), also known as spiny anteaters,[2] belong to the family Tachyglossidae in the monotreme order of egg-laying mammals. There are four extant species, which, together with the platypus, are the only surviving members of that order and are the only extant mammals that lay eggs.[3] Although their diet consists largely of ants and termites, they are no more closely related to the true anteaters of the Americas than to any other placental mammal. They live in New Guinea and Australia. The echidnas are named after a monster in ancient Greek mythology.
This used to be the discription section.
Evolution
Molecular clock and fossil dating suggest echidnas split from platypuses 19–48 million years ago. Echidnas evolved from water-foraging ancestors which returned to living completely on the land, even though this put them in competition with marsupials.[4] Because of this, it has been suggested that "oviparous reproduction in monotremes confers advantages over marsupials, a view consistent with present ecological partitioning between monotremes and marsupials."[4]
Taxonomy
Echidnas are classified into three genera. The genus Zaglossus includes three extant species and two species known only from fossils, while only one extant species from the genus Tachyglossus is known. The third genus, Megalibgwilia, is known only from fossils.
Zaglossus
The three living Zaglossus species are endemic to New Guinea. They are rare and are hunted for food. They forage in leaf litter on the forest floor, eating earthworms and insects. The species are:
- Western long-beaked echidna (Zaglossus bruijni), of the highland forests
- Sir David's long-beaked echidna (Zaglossus attenboroughi), described in 1961 and preferring a still higher habitat
- Eastern long-beaked echidna (Zaglossus bartoni), of which four distinct subspecies have been identified
The two fossil species are:
Tachyglossus
The short-beaked echidna (Tachyglossus aculeatus) is found in southeast New Guinea, and also occurs in almost all Australian environments, from the snow-clad Australian Alps to the deep deserts of the Outback, essentially anywhere ants and termites are available. It is smaller than the Zaglossus species, and it has longer hair.
Megalibgwilia
The genus Megalibgwilia is known only from fossils:
- Megalibgwilia ramsayi from Late Pleistocene sites in Australia
- Megalibgwilia robusta from Miocene sites in Australia
Echidna in pop culture
Knuckles the Echidna is a red echidna featured in the video game series Sonic the Hedgehog. Knuckles made his debut in Sonic the Hedgehog 3 for the Sega Mega Drive and Sega Genesis.
References
- ^ Groves, C. P. (2005). Wilson, D. E.; Reeder, D. M. (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Baltimore: Johns Hopkins University Press. pp. 1–2. ISBN 0-801-88221-4. OCLC 62265494.
- ^ Retrieved on 21 October 2007
- ^ "The Enigma of the Echidna" by Doug Stewart, National Wildlife, April/May 2003.
- ^ a b Phillips MJ, Bennett TH, Lee MS. (2009). Molecules, morphology, and ecology indicate a recent, amphibious ancestry for echidnas. PNAS. 106:17089–17094. doi:10.1073/pnas.0904649106
- Flannery, T.F., and Groves, C.P. (1998) A revision of the genus Zaglossus (Monotremata, Tachyglossidae), with description of new species and subspecies. Mammalia 62, 367–396.
- Parker, J., "Echidna Love Trains", "Scribbly Gum" online magazine.
External links
- "The Enigma of the Echidna" by Doug Stewart, National Wildlife, April/May 2003.
- Scribbly Gum - Australian Broadcasting Corporation online magazine, article "Echidna Love Trains": Echidna spotting, Trains (breeding behaviour), The amazing puggle (young), Species, Dreaming (REM sleep), Managing populations; June 2000