Talk:Hydra (genus)

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are there any pictures I can get on the Hydra(genus)?

- I'm personally concerned about the main image at the top of the article as it appears overtly phallic. Can another shot not be taken from a less pleasing angle? Trying to learn here. Thanks. — Preceding unsigned comment added by (talk) 11:54, 17 March 2016 (UTC)


"mac and roni" needs a citation and attribution. Wikipedia does not claim that things are beautiful. -Silence 06:05, 24 March 2006 (UTC)

What is "hydra are low power microscopical life forms" supposed to mean? It just sounds like gibberish. --scienceman 21:38, 2 August 2006 (UTC)

The original text read "Hydras are beautiful low power microscopical objects and are often studied by biologists. "

This has been mutated to the current form - it appears that some editors regard "Beautiful" as a POV statement ! Velela 08:11, 3 August 2006 (UTC)

Hydra vulgaris?[edit]

Isn't there a Hydra vulgaris as well?

Yes, roni is my best frriend!! love mac! it's a synonym for Hydra attenuata (see [1]). AxelBoldt 19:09, 14 May 2006 (UTC)

more information?[edit]

we need to have more information about hydras.

Yes-- 00:00, 2 July 2007 (UTC)

if you have some problum so just call:+923453052288(Mr.Johnson) —Preceding unsigned comment added by (talk) 15:33, 21 December 2009 (UTC) and mariner is used as reasearch also.

What is the approximate size of a hydra? Need both in metric scale and a familiar comparison.Samtunes (talk) 20:33, 31 July 2012 (UTC)samtunes

Biologically immortal?[edit]

I'm sorry but....biologically immortal?

Can we have more citations for this fact please? I'm no biologist but this sounds like its been either entirely made up or misinterpreted.

Citations is in the article. "Biologically immortal" doesn't mean that they live forever, it just means that their death probability doesn't increase with age. AxelBoldt (talk) 05:43, 13 January 2009 (UTC)

Radial Symmetry[edit]

The picture of a hydra doesn't appear to be radially symmetric. I assume this statement means that they can form a spherical shape but if they're not always in this shape how can they be radially symmetric? Can someone who knows more about this expand on it. 11:42, 6 July 2007 (UTC)

Radial symmetry is when an organism is symmetrical in any transverse section. I.e a section across the body produces a circular shape, whilst one across the tentacles produces a neat circle of circular cross sections. A longitudinal section would hover produce an asymmetrical form. Velela (talk) 10:43, 31 January 2008 (UTC) it to much understandable —Preceding unsigned comment added by (talk) 15:31, 21 December 2009 (UTC)


The whole artical needs to be edited to show Hydra in italics since this is the genus name. By scientific standard, when referring to an organism by it's genus and/or species name, the name should appear in italics. "Hydras", however, need not be in italics since this is not the scientific name. Marv101 (talk) 12:54, 2 March 2008 (UTC)


Wow, if you look at the history - tons of vandalism. I think semi-protection would be worthwhile. Timeroot (talk) 03:16, 18 February 2009 (UTC)


Is the plural of hydra "hydras", or is the word uncountable? --T.M.M. Dowd (talk) 17:03, 24 June 2009 (UTC)

I guess it all depends. Hydra is used as the scientific genus name and is, in that instance, incapable of pluralisation i.e. "..we observed a colony of Hydra viridis...."
But we also must accept that the name is widely used as a common name and as such Hydras is an acceptable pluralisation in English (both British English and American English). What is unacceptable is Hydrae because that makes all sorts of assumptions about the derivation of the scientific name and the rules of grammar surrounding it in its native language. Even if a scientific name was indubitably derived directly from a Latin name of which the plural was known the Latin plural would not be used as the pluralisation of common names still follows the pluralisation rule of the language within which it is quoted. Thus, for example, Octopuses and not Octopae.  Velela  Velela Talk   19:16, 24 June 2009 (UTC)
According to the Oxford English Dictionary, "octopi" and "octopodes" are both valid alternatives. Well, "valid" in that they have been used widely enough to warrant inclusion in the OED, which doesn't imply any kind of etymological integrity. The pluralisation rules of the English language seems to be more like what you'd call guidelines than actual rules. :P Anyway, the OED didn't have much on hydras/hydrae. Apparently, those lazy Romans and Greeks never saw the need to pluralise it themselves, seeing that there was only one Hydra and it was already dead. Does anyone know of a nice juicy reference on this? Personally, I propose that "hydra" should be the plural, the singular being "hydroth". (talk) 22:42, 4 February 2013 (UTC)
Noting my previous comments above, I would propose that we retain Hydra as the singular and use Hydribus as the 3rd declension ablative plural of a Greek noun in Latin . If we can't make a case for the ablative (by with or from Hydras) and have to stick to the boring Nominative case, then I am afraid we are stuck with Hydra again as the plural and unremarkably Hydra as the singular too. Ho hum.  Velella  Velella Talk   22:56, 4 February 2013 (UTC)

Schematic drawing error[edit]

The schematic drawing of the nematocyst is incorrect for the following reason: When triggered, the content of the cell is everted (like blowing the fingers out of an inverted rubber glove). The barbs that are shown to shoot out in the third part of the drawing should remain stationary, while the thread everts through the barbs. —Preceding unsigned comment added by (talk) 18:32, 18 October 2009 (UTC)

Paragraph removed[edit]

I removed the following paragraph from the Morphallaxis section, because I have searched for hours, but I have not been able to find a single reliable source for the claims made therein. At the end, I added some claims from other sources that sported claims not noted in this article, but which stated that their source was this Wikipedia article. The actual text I removed is in bold print (to include the text within the Citation needed template that is colored green):

Nineteenth-century biologists reported that the Hydra was such a simple animal that it was possible to force one through gauze to separate it into individual cells; if the cells were then left to themselves, they would regroup to form a hydra again. This experiment has not been repeated successfully in the 20th or 21st centuries;{{Citation needed|reason= : "The experiments of H V Wilson in the early part of this century seemed at first to suggest that contrary to any evidence for embryonic mosaicism, adult sponges were highly regulative. What Wilson (1911) did was to press a marine sponge through bolting cloth (a fine, stiff gauze sieve) and by doing so he separated the cells and the individual cells would settle on the bottom of a dish of sea water. If they were kept properly aerated, in a matter of few days, they re-formed new, small sponges. The rubble of cells reconstituted a new individual. Wilson interpreted these experiments as an example of regulation, where the separation made all the cells return to an embryonic condition and once the motile cells accumulated in balls, the cells on the outside re-differentiated into epithelial cells, while those in the interior turned into collar cells and amoebocytes.", "Besides their ability to regulate, hydroids also show evidence of cell migration and sorting out very similar to that found in sponges. If a hydroid is macerated with a small scalpel and reduced to a pile of mixed cells, it will recover and produce an individual polyp. (Hydroid tissue cannot be put through bolting cloth—the cells are too tightly cemented together). This reconstituted polyp is presumed (but not known) to be produced by the cells retaining their original fate and simply reorganizing, as we saw to be the case in sponges." |date=January 2011}} the remains of the hydra do not reform - all that is produced is "hydra soup". A similar experiment with sponges has been more successful; however, the cells produced will grow into new sponges instead of regrouping to form the original individual.

That text should remain on this talk page and not reintroduced to the article until a reliable source(s) can be found.– Paine (Climax!)  03:29, 8 November 2012 (UTC)


Quote: "The controversial unlimited life span of Hydra has attracted the attention of natural scientists for a long time."

So, it seems there's a controversy about the senescence of the hydra. I found nothing about it neither in the article nor elsewhere on the net. Can somebody tell more about that controversy? And if there is a controversy, I don't understand why the article takes an one sided position stating adamantly immortality, only immortality, nothing else but immortality.

And, by the way, I saw on the net a careless confusion between very long age and immortality. I don't understand why that difference is minimalized or even ignored. It's of a huge importance.Srelu (talk) 02:35, 9 April 2016 (UTC)

And the "life cycle" section doesn't explain anything about hydra death. Do they die of old age? Or do they die only due to external factors like starvation, dehydration, poisoning, being eaten, etc.? ~Amatulić (talk) 01:35, 25 July 2016 (UTC)
Most Hydra in temperate climates die at the onset of winter, probably through starvation, but leave behind the sexually produced resting eggs which hatch in the spring.  Velella  Velella Talk   09:10, 25 July 2016 (UTC)

dimensions not mentioned[edit]

Schematic drawing of a discharging nematocyst / add size info, this is an encyclopedia, it is VERY important to mention the size!!! — Preceding unsigned comment added by 2A02:587:410F:8100:7006:1E3A:DCA4:BE2C (talk) 13:58, 14 June 2016 (UTC)

How about at Cnidocyte where there is a diagram and an electron micrograph showing the size under magnification?  Velella  Velella Talk   19:56, 16 June 2016 (UTC)