Wednesday, July 1, 2015

Underwater Grossology – Part 1

In celebration of our Grossology exhibit, we present to you some of our tide pool animals. This week we’ll discuss the very popular California sea cucumber (Parastichopus californicus).

Normally a sea cucumber cruising around the shallow water and looking classy in red velvet may seem like the farthest thing from disgusting. But look a little deeper – into its gut, in fact, and you will see plenty of fascinating grossology at work.

First is its ability to eviscerate, a behavior common among sea cucumbers. Under great stress such as from a predator, sea cucumbers are able to eject their guts – not just their gut content but also the actual lining of the digestive system – in the direction of the danger as an emergency form of self-defense. The stringy gut material entangles the predator, slowing or stopping it while the cucumber escapes. If this defense works, the animal can then regrow its gut lining, which is taxing to its body but preferable to being eaten.

Please don’t squeeze sea cucumbers. Defensive eviscerating is a last ditch survival behavior that you don’t want to make them do, and you don’t want that stuff on your hands!

California sea cucumbers also eviscerate on an annual cycle, with the gut breaking down in late autumn and regrowing in winter and early spring. During that time they absorb nutrients through the respiratory trees in their anus. These organs, which normally facilitate oxygen exchange, can apparently also uptake nutrients.

Right now our California sea cucumber is not in its regenerative phase, and is eating with its mouth and using its anus to breathe and to defecate. You can see its cute sandy poops scattered around the tide pool. How gross is that?

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