--- title: "Sea Pig — Abyssal Sea Cucumber That Herds in Thousands on the Ocean Floor" url: https://thesea.org/scotoplanes-sea-pig/ date: 2026-03-03 modified: 2026-11-13 lang: en author: "Blane Perun" description: "Scotoplanes, the sea pig, is a deep-sea creature that walks on inflated tube feet, herds across the ocean floor in the thousands, and eats mud for a living. One of the strangest animals on Earth." categories: - "Bizarre Sea Creatures" image: https://thesea.org/wp-content/uploads/Bizarre-2-1024x572.jpg word_count: 2076 --- # Sea Pig — Abyssal Sea Cucumber That Herds in Thousands on the Ocean Floor [TheSea.Org](/)▸[Bizarre Sea Creatures](/bizarre-sea-creatures/)▸Sea Pig # Sea Pig — Scotoplanes globosa Deep Sea By [Blane Perun](/about-blane-perun/) April 15, 2026 9 min read What is a sea pig? The sea pig (*Scotoplanes globosa*) is a deep-sea sea cucumber — an echinoderm that walks on the ocean floor using inflated tube feet, herds across the abyssal plain in groups of hundreds or thousands, and feeds by processing sediment for organic material. Despite looking nothing like a cucumber, the sea pig is classified in the class Holothuroidea alongside reef sea cucumbers. It lives at depths of 1,000 to 5,000 metres and is one of the most abundant animals on the abyssal floor. Quick facts Scientific name**Scotoplanes globosa** ClassHolothuroidea — sea cucumber Size10–15 cm Depth**1,000–5,000 m abyssal floor** Locomotion**Inflated tube feet — walks on sediment** DietMarine snow — processes sediment GroupingHerds of hundreds to thousands DirectionOften faces upstream The sea pig is one of those deep-sea animals that looks like it was designed as a joke. Pale, translucent, sausage-shaped, with multiple rows of stumpy inflated legs and a cluster of sensory tentacles at one end, it walks slowly across the abyssal floor in the darkness 4,000 metres below the surface. Hundreds at a time. Seafloor cameras often show herds of them, all facing the same way, across the mud. On soft abyssal bottoms they are among the most commonly seen large animals, in a place most people never think about. Why is it called a sea pig? The name comes from the body shape — a pale, rounded, somewhat rotund form with multiple stubby legs, resembling a cartoon pig when viewed from the side. The comparison is loose but evocative enough that it stuck. *Scotoplanes* are not the only sea cucumbers called sea pigs — a few other deep-sea holothurians get the name — but *Scotoplanes globosa* is the most commonly referenced species. Its inflated tube feet are the most pig-like feature: they look like short, fat legs compared to the slender tube feet of most sea cucumbers. 5,000 mMaximum recorded depth 1,000sIndividual herd size 300–600Individuals in early trawl hauls ![Sea pig (Scotoplanes) walking on inflated tube-feet legs across the muddy abyssal seafloor](https://thesea.org/wp-content/uploads/v2-scotoplanes-sea-pig-how-do-sea-pigs-move-thesea-org-by-blane-perun.webp)Sea pig (Scotoplanes) walking on inflated tube-feet legs across the muddy abyssal seafloor How do sea pigs move? Sea pigs walk on inflated tube feet — locomotory appendages that are hydraulically inflated with seawater to create rigid, stumpy legs that push against the soft sediment. They also have papillae — sensory projections on the upper body surface — that are not used for locomotion. Movement is slow but directional. Sea pigs are often seen facing into the prevailing current rather than randomly. This is thought to position them to intercept food particles — mainly marine snow and organic detritus — carried in the bottom current. When food-rich sediment arrives from above — often following a whale fall or a bloom sinking from the surface — sea pigs aggregate in enormous numbers at the food source. Parasites that hitchhike on sea pigs Sea pigs are frequently found with **hitchhikers**: parasitic snails that feed on the body wall, tiny tanaid crustaceans, and juvenile king crabs that shelter underneath them. The sea pig is effectively an ecosystem for smaller organisms in the abyssal desert. What do sea pigs eat? Marine snow — the slow rain of organic particles from the surface ocean — and organic-rich sediment. Sea pigs process sediment by ingesting it and extracting organic compounds, then expelling the processed material. This makes them critical recyclers in the deep-sea ecosystem, releasing nutrients locked in sediment back into bioavailable form. Some evidence suggests they are also attracted to whale falls, where an enormous pulse of organic material creates a temporary bonanza in an otherwise food-poor environment. How do you identify a sea pig? Look for a plump, pinkish, see-through sea cucumber about 10 to 15 cm long, walking on six pairs of stubby legs, with antenna-like papillae sticking up from its back. Sea pigs belong to the genus *Scotoplanes* in the family Elpidiidae, order Elasipodida. Three species are currently recognised: *S. globosa*, *S. angelicus* and *S. mutabilis*. *S. globosa* is the one in most photos and videos. The body is bilaterally symmetrical, which is unusual for an echinoderm. It has six pairs of enlarged tube feet, largest at mid-body and smallest toward the rear, and ten buccal tentacles around the mouth that shovel in sediment. On its back are elongated papillae that look like antennae or ears. Scientists don't use them for walking, but they are built the same way as the feet, each with a muscular water canal running through the middle. The most common look-alike on the same seafloor is *Peniagone*, another elpidiid sea cucumber. On Pacific seafloor video, *Scotoplanes* can be told apart by its two pairs of antenna-like papillae, whereas *Peniagone* has a single pair. ![Close-up of a translucent pink sea pig showing its internal gut, tube-feet legs and feeding tentacles](https://thesea.org/wp-content/uploads/v2-scotoplanes-sea-pig-how-does-a-sea-pig-work-inside-thesea-org-by-blane-perun.webp)Close-up of a translucent pink sea pig showing its internal gut, tube-feet legs and feeding tentacles How does a sea pig work inside? It is a hydraulic animal: the legs are moved by water pumped through the skin. In most sea cucumbers, each tube foot is powered by a small internal bulb called an ampulla. Elpidiids replaced those bulbs with cavities in the skin. That lets the feet grow much larger, so they work as legs and hold the body up on very soft mud. As a sea pig walks, it ploughs through the top layer of sediment and disturbs the small animals living there. When disturbed, some sea pigs can swim short distances using lobes at the front and rear of the body, and a few species spend a lot of time just above the bottom. Like other sea cucumbers, sea pigs have a simple nerve network without a central brain, and their skin contains holothurin, a toxic saponin that deters many predators. Unlike most echinoderms, they have a single gonad, so each female has one ovary and each male one testis. Studies have found active egg and sperm production in both sexes, which suggests a different breeding strategy from many related deep-sea cucumbers. They are adapted so completely to cold, high-pressure water that specimens brought to the surface quickly fall apart. That's why you won't see a living sea pig in a public aquarium. What do sea pigs eat, and how do they find it? They are deposit feeders that pick the freshest organic matter out of the mud, and they can smell a rich meal from a distance. All deep-sea holothurians feed by swallowing sediment and digesting the organic particles in it, but sea pigs are picky about it. Studies of *S. globosa* show it strongly prefers fresh phytodetritus, the remains of plankton blooms that have just sunk from the surface, over older and poorer mud. Experiments also show that sea pigs use smell to locate rich food falls such as whale carcasses, and they gather around them in large numbers. On video, groups of sea pigs are often seen all pointing the same way, facing upstream. That position probably helps them pick up the scent of food carried along by bottom currents. Because they gather where food is, sea pigs are patchy. Early trawl collections brought up groups of 300 to 600 individuals at once, and seafloor cameras often show hundreds within view. Aggregations may also bring mates together. Where do sea pigs live, and who lives on them? On abyssal plains in the Atlantic, Pacific and Indian Oceans, mostly from about 1,200 to 5,000 m, often with hitchhikers. *Scotoplanes* occurs on deep soft-bottom plains in all three major oceans, and related elpidiids reach Antarctica. Off Oregon and Washington, the Ocean Observatories Initiative cameras have filmed them from about 1,230 m on the continental margin to about 2,600 m at the base of Axial Seamount. They share these habitats with brittle stars, other sea cucumbers, sea pens, grenadiers and hagfish. Sea pigs are small ecosystems in their own right. Parasitic snails attach to and feed on their body wall, and tiny tanaid crustaceans also live on them. In 2016, the Monterey Bay Aquarium Research Institute filmed juvenile king crabs (*Neolithodes diomedeae*) at about 1,260 m sheltering beneath sea pigs. Researchers concluded the crabs gain protection from predators by hiding there. The genus was named by the Swedish zoologist Hjalmar Théel in 1882, in his report on the holothurians collected by the HMS *Challenger* expedition of 1872 to 1876, the voyage that founded modern oceanography. Sea pigs haven't been assessed for the IUCN Red List. Researchers see their dependence on undisturbed soft sediment as a reason for caution about deep-sea mining and bottom trawling on the abyssal plains. “The first time I saw ROV footage of thousands of sea pigs crossing an abyssal plain together, I genuinely could not process what I was seeing. It looks impossible — a living carpet 4,000 metres down in total darkness.” — Blane Perun, TheSea.Org ![Herd of sea pigs (Scotoplanes globosa) crawling together across the muddy abyssal plain](https://thesea.org/wp-content/uploads/v2-scotoplanes-sea-pig-overview-thesea-org-by-blane-perun.webp)Herd of sea pigs (Scotoplanes globosa) crawling together across the muddy abyssal plain **Related on TheSea** - [Red Handfish](/red-handfish/) - [Red-Lipped Batfish](/red-lipped-batfish/) - [Colossal Squid](/colossal-squid/) Frequently asked questions What is a sea pig? A sea pig (Scotoplanes globosa) is a deep-sea sea cucumber that walks on inflated tube feet across the abyssal ocean floor at depths of 1,000 to 5,000 metres. It feeds on marine snow and organic sediment, travels in herds of hundreds to thousands, and is one of the most abundant large animals on the abyssal plain. Why is it called a sea pig? The name comes from the body shape — a pale, rounded, somewhat rotund form with multiple stubby inflated tube feet that resemble pig legs when viewed from the side. The resemblance is loose but memorable enough that the name stuck. How deep do sea pigs live? Between 1,000 and 5,000 metres on the abyssal floor — well beyond sunlight, in near-freezing water under enormous pressure. They have been filmed from about 1,230 m off Oregon down to abyssal depths. What do sea pigs eat? Marine snow and organic-rich sediment. Sea pigs ingest sediment, extract organic compounds, and expel processed material. They are critical nutrient recyclers in the deep-sea ecosystem. They also aggregate at whale falls where a large pulse of organic material provides a temporary bonanza. Do sea pigs travel in groups? Yes — in herds of hundreds to thousands of individuals. ROV footage of the abyssal plain frequently shows dense aggregations of sea pigs moving together. They consistently walk into the current, likely to intercept food particles carried in bottom water flow. Is the sea pig a real animal? Yes — completely real, well documented, and extraordinarily abundant in the deep ocean. It was not well known to the public until ROV footage became widely available. Scotoplanes globosa is a valid species with a long research history in deep-sea biology. Can you keep a sea pig in an aquarium? No. Sea pigs are adapted to cold, high-pressure deep water and fall apart when brought to the surface, so no public aquarium displays them alive. Are sea pigs poisonous? Their skin contains holothurin, a toxic saponin found in many sea cucumbers that deters predators. They pose no risk to people, who never encounter them alive. Explore squid, fish & oddities Squid, fish & oddities [Sea Pig — abyssal sea cucumber that herds in thousands across the ocean floor](/scotoplanes-sea-pig/) [Blob Sculpin — the deep-sea fish that guards thousands of eggs on the seafloor](/blob-sculpins/) [Cuvier’s Beaked Whale — dives deeper than any other mammal, 2,992 metres](/cuviers-beaked-whale/) [Bobbit Worm — ambush predator buried in reef sediment that can bisect fish](/bobbit-worm/) [Ocean Sunfish — heaviest bony fish on Earth at 2,744 kg](/sunfish/) [Mexican Walking Fish — the axolotl that regrows lost limbs and is critically endangered](/mexican-walking-fish/) Sources & further reading - Théel (1882), Report on the Holothurioidea, *Challenger* Reports, Zoology vol. 4 - Hansen (1972), photographic evidence of a unique type of walking in deep-sea holothurians - University of Washington Interactive Oceans: Sea Pig (*Scotoplanes globosa*) - Monterey Bay Aquarium Research Institute (2016), juvenile king crabs sheltering under sea pigs Continue reading More from the Deep Sea [Deep SeaGulper EelThe fish with a mouth larger than its own body and a bioluminescent tail lure. ](/gulper-eel/) [Deep SeaVampire SquidNeither squid nor octopus — the passive deep-sea feeder with bioluminescent defences. ](/vampire-squid/) [Bizarre Sea CreaturesBizarre Sea Creatures GuideEvery deep-sea species that defies what you thought you knew about marine life. ](/bizarre-sea-creatures/) BP Last updated May 18, 2026 Written by Blane Perun Blane Perun has been exploring Earth’s oceans and marine life for over 25 years. Founder of TheSea.Org in 1999, underwater photographer, coral aquaculture pioneer, and explorer of 80+ countries. [About Blane Perun →](/about-blane-perun/) [More on Bizarre Sea Creatures →](/bizarre-sea-creatures/)