5 things you didn't know about sea pigs

February 22, 2018, 8:24 a.m.
Sea pig, a deep sea creature.
Photo: Wired/Screenshot

1. Yes, sea pigs actually exist

It's an alien, it's a cucumber, no — it's the sea pig! It's hard to imagine something small and pink that snarfles its way across the ocean floor like a pig in a pen, but here it is. Sea pigs are sea cucumbers, a class of animals called echinoderms that also includes sea urchins and starfish.

Maybe next time you see a sea star, you'll look out to the ocean's horizon and think of Scotoplanes, this strange cousin of your familiar tide pool creatures.

2. Sea pigs are found in all of the oceans of the world

While you might not have heard of them before, they're actually all over the place — well, as long as it's very cold and very deep. They've been found as far as 3.7 miles under the ocean surface.

Encyclopedia of Life notes that they "are restricted to deep and cold parts of the world ocean, where they are the dominant large animals in most areas, often comprising more than 95 percent of the total weight of animals on the deep-sea floor."

While they're abundant, you're probably never going to see one since they are truly creatures of the abyss.

3. Sea pigs are scavengers

These small creatures prefer an easy meal, mostly one that they don't have to catch. While it sounds lazy, this scavenging is actually a great service for the ocean ecosystem, as sea pigs act like vacuum cleaners tidying up the ocean floor. If there's a carcass that sinks to the floor, there's likely a little herd of piggies zeroing in on it for lunch.

Australian Geographic notes, "Sea pigs can congregate in enormous numbers when there’s a meal to be had — biologists have spotted herds of 300-600 individuals, and weirdly enough, they all face in the same direction, presumably to take advantage of the detritus floating in the current."

4. They're also like earthworms

The comparison of Scotoplanes to land-dwelling creatures doesn't stop at barnyard animals. Marine biologist David Pawson of the National Museum of Natural History compares them to another weird but helpful animal. WIRED explains:

When they’re not gobbling marine snow or the occasional whale juice, sea pigs are going after all kinds of microbes on the seafloor. Which is just as well, because such microbes are consuming a whole lot of oxygen down there. When the sea pigs pass this microbial mud through their digestive system, they of course absorb all the good nutrients, but also themselves end up adding oxygen back into the muck and pooping it out on the seafloor. "They're like earthworms," says Pawson. "They sort of process the deep-sea mud and make it livable for other animals because they've increased the amount of available oxygen in it."

5. They've got crabs (in a good way)

Sea pigs aren't the only ones making a life at the bottom of the ocean. Baby king crabs make a go of growing up there as well. And those baby crabs, an easy meal for predators, need protectors. They find just such a protector in the unlikely shape of a sea pig.

The Monterey Bay Aquarium Research Institute reports that in 2011, researchers noticed baby king crabs clinging to quite a few sea pigs. In reviewing footage of other deep sea creatures, they witnessed this savvy survival strategy:

All in all, the researchers examined about 2,600 sea cucumbers and found that almost one quarter of them carried crabs. Virtually all of the crabs were juveniles of a species of king crab called Neolithodes diomedeae. The researchers were surprised to discover that virtually all (96 percent) of the juvenile Neolithodes crabs they saw in deep muddy-bottom areas were clinging to sea pigs.

It doesn't happen everywhere. Rather, juvenile crabs hitch a hiding place on sea pigs only in places where sea pigs are "the largest benthic structure available as shelter."

Curious to learn more? Check out this fun, fact-filled video:

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