Sea Cucumbers

Story

The Florida Museum of Natural History is a center of sea cucumber research and you might wonder why on earth anybody would spend a lot of energy studying these bizarre, weird-looking animals and there’s a couple of reasons.

One, they are one of the most valuable marine resources in the tropics. They are eaten, especially in East Asia, and fetch very high prices, and as a result many countries that are on tropical shores harvest them in large numbers. This has led to huge depletions of their populations and management crises, and of course a lot of colorful characters are involved in this bêche-de-mer trade.

In addition, their biology is fascinating. These are really bizarre animals. They are echinoderms; their closest relatives are sea urchins. You don’t see much of a sea urchin in these, but think about some of the oddities they do. For example, they can throw out their gut when they’re not happy and regenerate it. The entire intestine can be pushed out of the animal and left behind and a new intestine is grown. They breathe through their butt. They have a lung that opens through their anus and they breathe water in through their anus that dilates and pushes things in there, and — fishes live in this lung! Pearl fish will crawl in and out of the sea cucumber’s butt to live inside its water lungs.

If that was not enough, they have these bizarre tubes that they can expel — also through their butt — that elongate and become incredibly sticky, white, spaghetti-like threads and these will stick to anything that touches it, including you. It’s a really unpleasant experience to have yourself covered in this and try to pull it off your arm hairs, and of course if you happen to be a fish you’ll probably get so clogged up that you will die and suffocate as a result. So they are very well-defended animals and very successful until people started harvesting them for culinary purposes.

Gustav Paulay
Curator, Invertebrate Zoology
Florida Museum of Natural History