collision detection: How to make an artificial shark uterus

September 01, 2006

How to make an artificial shark uterus

So, apparently some Australian scientists are attempting to create artificial shark uteruses -- so that they can prevent fetal sharks from eating each other in the womb.

Yes, you read that correctly. Here's the deal: The average female grey nurse shark begins her pregnancy with about 40 embryos in her two uteruses. But it takes a year for the baby sharks to gestate, and by the time they're ready to be born, there are only two left -- one in each uterus. Why? Because by four months they've developed a full set of teeth, and the strongest begin cannibalizing the weaker ones. Ay yi yi. I'd heard of wild dingos getting into deathmatches right after being born, but this takes the whole red-in-tooth-and-claw stuff up to the next level.

Anyway, the grey nurse shark population is apparently critically endangered, and since they're the top predators in the oceanic food chain, the ecosystem could be unpredictably unbalanced if they all vanish. So the scientists are trying to develop an artificial shark uterus so they can capture a pregnant female, flush out the embryos, and raise them independently so they can all be born.

Of course, as Slate wondered, maybe this attempt to tinker with Mother Nature is doomed to failure. Maybe the embryo sharks need to feed on one another to survive long enough to be born; and maybe the pre-birth contest serves to winnow out sharks that wouldn't prosper in the wild anyway. Scientists aren't sure, as an AFP story notes:

No accepted explanation has been established for why the grey nurse sharks take sibling rivalry to such extreme lengths.
"It would seem logical that the intra-uterine cannibalism does confer some sort of evolutionary advantage, somewhat similar to the survival of the fittest, but it may be the luck of the draw because even the biggest could be attacked," Otway said.

Well, that's gotta be a conversation-stopper at cocktail parties. "So, what do you do for a living?" "Oh, I design artificial shark uteruses to prevent inter-uterine embryo cannibalism."

(Thanks to Franco for this one!)

Posted by Clive Thompson at September 01, 2006 02:29 AM

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Comments

"Scientists aren't sure"

Do you know what - I cannot hear this often enough! Because when Scientists are certain about things, they usually turn out to be wrong. :)

I had noted this unusual selachian behaviour a few years ago, and in fact used it as part of the setting for an cRPG I was designing at the time. I want to point out that as long as it does not confer significant competitive disadvantage, there is no reason to conclude that it must confer a significant competitive advantage.

There is a nasty tendency towards teleological thinking in this sort of biology which deserves more critical thinking; Stephen Jay Gould was one of the first people I know of to observe that we cannot know which elements of an organism are there because they conferred selective advantages and which are there purely by chance.

Best wishes!

Oh, and thanks for the link to the Seal Generator. Most awesome. :D

Posted by: Chris Bateman at September 1, 2006 6:51 AM

AAAAAAAAAAAAAAAAAAAAAA!!!!!!!!!!!!!!!!!!!!

Posted by: Dave Sandoval at September 1, 2006 10:04 AM

You know, I woke up this morning wondering how to go about making a shark uterus, and then you end up writing about it. Serendipity! ;)

I personally love it when science tries to tinker with nature. It is usually a devastating failure, and provides wonderful sidebar comic relief. I'm not a marine biologist, but it seems that if you circumvent one of the constants in shark development, then release these things into the wild, they won't be top of the food chain for long.

-j

Posted by: digital_blue at September 1, 2006 12:53 PM

Mmm, I dunno...interfering with natural selection at work? On sharks keen to commit intrauterine cannibalism? This should be interesting.

Posted by: Lyle Sinrod Walter at September 1, 2006 2:24 PM

Just when I was getting peevish about being pregnant, you bring it all back into perspective.

I'm really glad to be having just one baby.

Who hasn't eaten all her brothers and sisters in the past few months.

Goodness.

Posted by: Laura at September 1, 2006 7:34 PM

Chris, you were going to use this in a game design? Excellent!

Digital_blue, Lyle ... heh, yeah, that's the million-dollar question, eh? It reminds of the strangely not-that-bad sharksploitation flick Deep Blue Sea from a few years back. "What did you do to those sharks' brains?" I won't give away the story, but trust me, it's kind of fun.

Laura, congratulations! I'm glad your child will not have to engage in intrauterine knife fights.

Dave, my thoughts exactly.

Posted by: Clive at September 2, 2006 6:39 AM

I think I go to very different cocktail parties than you, Clive - at most of the ones I go to, that sentence would definitely get a conversation going!

Posted by: debcha at September 5, 2006 11:05 AM