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If you have to go, go big!

When you want to learn about the biology of a charismatic species, any species really, sometimes you end up learning about the grosser side of life too.  Thats kind of how I came to take this picture last week in Mexico, where I and several others from the team at Georgia Aquarium have been doing research on whale sharks lately (see several other blog posts heareabouts).  It was taken during an aerial survey we did from an altitude of 1,500 ft in a Cessna 206 and shows a whale shark that has just defecated.  Now, whale sharks tend to do everything on a giant scale, so perhaps we shouldn't be too surprised, but I estimate the animal to be between 8 and 11m (25-35ft) in length and so, based on that estimate, thats a cloud of poo behind him thats over 30ft in diameter!  Its unusual to see wild sharks in the act of pooping, but this group of animals was so numerous and feeding so heavily, that you could actually see several clouds like this at any given time.  Whats feeding heavily got to do with it?  Well, unlike mammals, which tend to have a relatively fixed gut passage time for food, a lot of cold-blooded critters can, well, sort of push it out the back end, simply by pushing more in the front end.

Far from being a trivial observation of one of life's less savoury moments, it could actually become a really important research opportunity if we can manage to catch some of that magical egesta in a container of some sort, for analysis back at the lab.   Scientists can do all sorts of stuff with poo, like looking for parasite eggs or other pathogens, sequencing the DNA of both the shark and its prey species, or comparing nutrient values of food (from plankton tows) and comparing them to values from faeces to work out how much nutrition they are gaining from their food.  Its a great way to learn a lot in a short time and do it in a totally non-invasive way.

Mostly though, its a cool photo to gross people out at parties...

Reader Comments (9)


August 6, 2010 | Unregistered Commenterenel

kõhutuuled, peeretas lihtsalt :)

August 7, 2010 | Unregistered Commenterkol

If anyone speaks Estonian, now would be a good time to chime in!

August 7, 2010 | Unregistered CommenterAl Dove

kõhutuuled, peeretas lihtsalt :)
It means: stomach wind, he just farted!

August 7, 2010 | Unregistered Commenterkiku

That's so funny. Hello to all the Estonian readers, I see there's a lot of you visiting lately! Thanks for visiting :-)

August 7, 2010 | Unregistered CommenterAl Dove

no sittuv vaal ei ole eriti huvitav teema.

August 8, 2010 | Unregistered Commenterascx

May I suggest a different DTF story then. Perhaps this one?

August 8, 2010 | Unregistered CommenterAl Dove

holy crap!

August 8, 2010 | Unregistered Commentererik

That's a cool picture. I wonder how long the poo stays around? Could you track a shark with it?

August 20, 2010 | Unregistered CommenterSam W

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