The amphibian Xipe Totec

14 April 2006

Spring, as the frenzily copulating Swainson’ses across the street will tell you, is a time for reproduction, rebirth and regeneration. But Nature, scrupulous accountant that he-she is, demands competition, carnage and sacrifice in return for all that blooming Qi. As Darwin put it in The Origin:

We behold the face of nature bright with gladness, we often see superabundance of food; we do not see, or we forget, that the birds which are idly singing round us mostly live on insects or seeds, and are thus constantly destroying life; or we forget how largely these songsters, or their eggs, or their nestlings are destroyed by birds and beasts of prey; we do not always bear in mind, that though food may be now superabundant, it is not so at all seasons of each recurring year.

And while, as Darwin notes, we may personally do our best to ignore the harsh realities of the season, our religious traditions do their darnedest to remind us. Some one billion or so practicing Catholics are fasting today, Good Friday, ostensibly to mark the date a dude was “nailed to a tree for saying how great it would be to be nice to people for a change” (in the words of Douglas Adams). Jews will be celebrating their own spring holiday, Passover, this weekend, remembering a spate of plagues, the decimation of a reproductive cohort, and a hasty flight into a forbidding desert.

The Mesoamericans had their own grisly spring rites, centered around this guy:

Xipe Totec, “Our Lord the Flayed One”…Sort of an Aztec cross between Demeter and Leatherface.

Which brings me to this article appearing in this week’s issue of Nature, documenting an odd behavior observed in one species of a curious group of legless amphibian known as caecilians (you’re breaking my heart). It seems that the devoted mommies offer up their own skin (amounting to up to 1/7th of their own body weight!) as a meal for their recently hatched young:

While this kind of parental investment is rather common in the animal kingdom (think milk and placentas), this is a rather dramatic example of motherly love to say the least. Interestingly, in other species of caecilian that give live birth, the young feed on the lining of their mother’s oviduct during gestation, which the authors of the current study propose as a possible precursor behavior to the skin-snacking (I misread the abstract, the authors in fact suggest the reverse). As mentioned in this news article on the study it is fairly common for other amphibians to feed on their old skin after shedding.

Happy spring and don’t forget to give mom a call this weekend!

Postscript:

Head on over to Rigor Vitae and Afarensis for much more. Carel’s post is accompanied, as per usual, by some awesome art (this time a Scaphiopus couchii doing his/her best Gene Kelly impression).

12 Responses to “The amphibian Xipe Totec”

  1. Chelsea Says:

    I’m really mad at myself for letting you post this before me.

    You’re awfully negative for focussing on the nailing part. Although – do you mean to make the point that from a Darwinian competition standpoint, the Romans or the Jews brutalized Jesus as a way of knocking out their competition????

    If you were really hot shit you would have posted this not only before me, but yesterday, and totally gone mad with Last Supper/First Supper musings.

    Swainson’ses?????

  2. microecos Says:

    Chelsea,

    Thanks for the link, but don’t let my post hinder you! I’d like to hear what you have to say about these critters, especially since it sounds like you’ve read the actual paper and I’ve only made it through the abstract so far. Do they mention anything about the fact that caecilians have skin covering their eyes?

    I don’t mean to be negative, and I wasn’t really trying to come up with any adaptive explanation for the cruxifiction of course. I find both evolutionary psychology and coming up with “scientific” explanations for miracles a waste of time. I guess I was just interested that the spring rituals of different cultures are so centered around suffering and death (even if those are couched within a broader message of salvation).

    The communion angle occurred to me but I forgot to throw it in! I’m tardy by nature.

    You’ve got a problem wiht my neologisation?

  3. Carel Says:

    Nice post, Neil! As usual, we’re thinking on parallel lines. Looks like you also not only scooped me on this story, but on the hokey Simon & Garfunkel reference. Lemme know if you’d like me to email you a pdf of the Nature article. It didn’t mention the skin covering their eyes (I think the aquatic Typhlonectid caecilians have functional eyes).

  4. coturnix Says:

    Hi, do you have a valid newsfeed (RSS or ATOM)?

  5. Neil Says:

    Thanks Carel. Your “Cecila” pun puts my parenthetical throw-away joke to shame. Sadly, it’s not for lack of access that I (still) haven’t read the article but simple procrastination. This site led me to me that Boulengerula might be blind. This photo too.

    Coturnix, wordpress tells me that its https://microecos.wordpress.com/feed/, but I must admit I’m not feeding yet.


  6. […] And it seems that fruit flies are always changing their spots, light side, dark side, they have no loyalty. Mon Calamari Jedi Knight Pee-Zed Myers has the report on their outer rims. The galaxy is home to many bizarre creatures, such as the dermophagous sicilians caecilians that feed their skin to their young as posted at Microecos, and Brad “Han Solo” Hoge at HUNBlog discusses director Peter Jackson’s assertions about why we like monster movies. And Professor “Chewie” Quippy wants you to accept the theory behind his new sexual cue ocular protection equipment. The question is, are the men or women the beasts in this matter? […]


  7. Nice post. And I may be misremembering this, but don’t we too have skin covering our eyes? Transparent skin?

  8. Neil Says:

    Thanks Jeremy!

    You are correct: the cornea is derived from the external ectoderm, a tissue layer that also forms our skin as well as the lining of our nose and mouth. Broadly speaking the cornea could be thought of as transparent skin.

    In caecilians, who generally live underground, the eye is often degenerate and is sometimes covered by actual skin (i.e. dermis) and in some cases even by bone.

    Our pineal gland, located near the center of our brain and which regulates circadian rhythyms, is probably a degenerate “third-eye” that detected light and dark in early land vertebrates. During evolution it somehow became covered with skin and bone and sank deep into the brain in later tetrapods.


  9. […] My post on caecilian skin feeding has made it into the latest edition of available The Inoculated Mind. […]


  10. […] I’m looking at you] can barely hold a candle to the actual feats of urodeles and their skin-snacking cousins the […]

  11. Neil Says:

    I think I meant “frenziedly”


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