Sea cucumbers: not vegetables!

What’s soft, squishy, able to spill its guts and found in most Seattle Aquarium habitats? The sea cucumber! These invertebrates (animals without backbones) can confuse or harm predators by expelling their internal organs—literally spilling their guts—along with a toxic substance, in the direction of an attack. The missing organs regenerate in one to five weeks.

The photo below features a mysterious creature recently spotted on the window of the “Only in Hawaii” exhibit. Is it a mollusk? A large sea slug? Look closely, and you may be able to make out the tiny white tube feet of this white-spotted sea cucumber. It got us thinking about other sea cucumbers that may go unnoticed while most of our attention is on the charismatic Giant California sea cucumber in the Life on the Edge exhibit. Read on to discover some of our fave sea cucumber species at the Seattle Aquarium, then plan a visit to come look for the animals in their habitats!

White-spotted sea cucumber
White-spotted sea cucumber, Actinopyga varians

Burrowing sea cucumbers, Cucumaria spp.
Often only the feeding tentacles of these burrowing sea cucumbers are visible, since they tend to keep their bodies tucked away under sediment or rocks. Look for these animals in several our exhibits, including Life on the Edge and Crashing Waves.

Black sea cucumber, Holothuria atra
Look for Hawaii’s most common, large sea cucumber in several windows of the Pacific Coral Reef exhibit (an interpreter in blue will be happy to help you look!). The cucumber’s body is black in color but may often be covered in a fine layer of white sand. Although this species is eaten and has some commercial value in certain parts of the Pacific, it contains holothurin and is toxic unless properly prepared. Better to stick with the recommendations on the Seafood Watch list!

Slipper sea cucumber, Psolus chitonoides
Often referred to as the creeping pedal cucumber or the armored sea cucumber, this creature is easily mistaken for a chiton or even a clump of sponge. It’s easier to see this animal’s features when the dramatic feeding tentacles are suspended—or when it’s on a window and its hundreds of tube feet can be observed, like in our photo. Look for slipper sea cucumbers around Life on the Edge, Window on Washington Waters, and especially in the rocky reef exhibits of the Puget Sound Fish exhibit. Juveniles can often be spotted in the Crashing Waves exhibit.

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