Sea Pig

Despite their name, Sea Pigs are actually a genus of unusual sea cucumbers and are related to starfish and sea urchins. They are part of the Elpidiidae family. These interesting little creatures live at extreme depths on the bottom of the ocean, across many of the world’s oceans.

Appearance

Sea Pigs are aptly named for their pig-like appearance, with near-transparent creatures lack eyes and a ring of tentacles around their mouth.

They are known for their stilt-like tube feet that elevate their bodies above the soft mud and use water cavities within their skin to inflate and deflate their puffy legs for movement.

Despite their usual mode of transportation, Scotoplanes can swim when disturbed and some species even spend significant time floating in the water column. While walking or swimming, they use their tentacles to sense their surroundings.

To remain at extreme depths, the Sea Pig uses a respiratory tree. Rather than having traditional lungs, it breathes from its anus.

Habitat

These deep-sea marine creatures inhabit the abyssal and hadal depths worldwide, including deep-sea trenches. They are found at depths ranging from 2,100 to 6,770 meters.

While they are found in most oceans, including the Pacific and Indian Oceans, and the deep sea off Tasmania, they have not yet been observed in the North Atlantic Ocean.

Diet

Sea Pigs play a vital role in the deep ocean ecosystem, acting like vacuum cleaners on the ocean floor. They are detrital feeders that selectively feed on fresh, nutrient-rich organic particles less than 100 days old. They often gather as large groups of Sea Pigs around whale falls and other nutrient-rich food sites.

Facing into the current, they use their sense of smell to detect new food sources, and their populations can boom after events like El Niño or La Niña, which bring more nutrients from the surface to the seafloor. Their scavenging nature is essential for maintaining the health of the deep-sea environment, cleaning up otherwise untouchable areas of the ocean.

Reproduction

Unlike most echinoderms, Scotoplanes have a unique reproductive system, with both males and females having a single gonad – one testis in males and one ovary in females. Although scientists know that they reproduce by laying eggs, their mating system remains a mystery, as does their lifespan.

Threats

While parasites pose a threat, the Scotoplanes’ unpalatable taste and poisonous skin help them survive in large numbers. Their skin contains holothurins, a toxic chemical that deters most fish and other potential predators.

Their delicate bodies are adapted to the extreme pressures of the deep sea, making them incredibly vulnerable outside their habitat. They cannot survive above 4,000 feet below the surface and easily disintegrate if brought up to shallower waters or caught in fishing trawlers.

Facts About the Sea Pig

1. They have a translucent body, sometimes revealing their guts and even parasites living inside.
2. Their dorsal papillae, small bumps on their backs, may help them “smell” the water for food.
3. Juvenile crabs, like the King Crab, sometimes hitch a ride on sea pigs for protection against predators.
4. The scientific name for the Sea Pig is Scotoplanes, which means “dark wanderer.”
5. They were first discovered in the late 1800s during the H.M.S. Challenger expedition.

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