I was recently told and shown a picture of an amazing little sea creature, the humble Sea Pig. I had never heard or seen a sea pig before so I thought I would do a little research for you all 🙂
The Sea Pig is known as Scotoplanes and is is a genus of deep-sea holothurian echinoderm of the family Elpidiidae, order Elasipodida. Scotoplanes live on deep ocean bottoms, specifically on the abyssal plain in the Atlantic, Pacific and Indian Ocean, typically at depths of over 1000 meters. Some related species can be found in the Antarctic. Scotoplanes (and all deep-sea holothurians) are deposit feeders, and obtain food by extracting organic particles from deep-sea mud. Scotoplanes globosa has been observed to demonstrate strong preferences for rich, organic food that has freshly fallen from the ocean’s surface, and uses olfaction to locate preferred food sources such as whale corpses.
Scotoplanes, like many sea cucumbers, often occur in huge densities, sometimes numbering in the hundreds when observed. Early collections have recorded 300 to 600 individual specimens per trawl. Sea pigs are also known to host different parasitic invertebrates, including gastropods (snails) and small tanaid crustaceans.
Members of the Elpidiidae have particularly enlarged tube feet that have taken on a leg-like appearance, and are the only instance of legged locomotion amongst the holothurians, using water cavities within the skin (rather than within the leg itself) to inflate and deflate the appendages. These legs, in conjunction with their large, plump appearance (about 6 inches/15 cm long) have suggested the common name “sea pig”. There are other genera of Elpidiidae with a similar appearance that have also been referred to as “sea pigs”.
Sea Pig Taxonomy and Scientific Specification
> Scotoplanes clarki
> Scotoplanes globosa
> Scotoplanes hanseni
> Scotoplanes kurilensis
> Scotoplanes theeli
Scotoplanes are known to form large groups. There have been reports of groups comprised of more than 1.000 individuals while early trawling records indicate an average of 300-600 caught specimens per trawl. It is believed that sea pigs are not actually social animals. They simply gather where food resources are abundant.
Sea pigs are deposit feeders that obtain their food by extracting organic particles from deep-sea mud. They have a high preference for rich and organic sources that have recently fallen from the ocean’s surface (e.g. a dead whale). They mainly use their sense of smell to detect their food. This is why they are commonly found facing towards the prevailing currents.
They use the ring of tentacles that surrounds the mouth to feed and absorb nutrients.
Sea Pig Facts
1. “Sea Pig” is a pretty accurate description. Sea pigs earned their moniker from their puffy legs and plump, oval-shaped pinkish bodies.
2. They fit in the palm of your hand. Sea pigs tend to be about 4-6 inches long.
3. Sea pigs live in the deepest part of the ocean. Sea pigs are found in the deepest abyssal depths of the world’s oceans, as far as 3.7 miles under the ocean surface.
4. Scientists have known about sea pigs for more than 100 years. They were first described by Swedish zoologist Hjalmar Théel in 1882. Théel described about 65 new species discovered by the British research ship HMS Challenger during her round-the-world expedition of 1872-1876.
5. They get around by walking on the seafloor. Sea pigs have five to seven pairs of enlarged tube feet. These “walking legs” are hydraulically operated appendages that can be inflated and deflated to move around.
6. Those aren’t antennae — they’re also feet. Although they look like antennae, the structures on the top of the sea pig’s head are actually feet. These upper papillae are modified tube feet, like the animal’s “walking legs.” They may help propel the sea pig along the ocean, or they may have a sensory function, helping it detect the chemical trail of a tasty meal.
7. Sea pigs scour mud for delicious scum. Sea pigs are deposit or detrital feeders, eating bits of decaying plant and animal material found in deep sea mud. Their mouths are surrounded by a ring of feeding tentacles that they use to sift through the mud and grab onto food. Sea pigs are especially fond of food that has recently fallen from the ocean’s surface, like a whale corpse.
8. They can sometimes be found in large gatherings. Sea pigs often occur in aggregations of many hundreds of individuals. It’s not because they enjoy each other’s company. It’s believed sea pigs tend to gather where food resources are abundant. Thus, many hundreds of sea pigs will be attracted to a dead whale carcass on the seafloor and gather at the spot to feast.
9. In these large gatherings, sea pigs will often all face in the same direction. It might look eerie — hundreds of sea pigs coating the seafloor, all orienting in the same direction. But there’s a good reason for it. Sea pigs usually face into the prevailing current, presumably so they can detect decaying goo and find the best feeding sites, according to the Echinoblog.
10. Sea pigs host several weird parasites. Sea pig parasites include small snails and crustaceans that bore holes in their host’s bodies and feed on them internally. Check out Echinoblog for photos.
Sea Pig Videos
True Facts about Sea Pigs
Sea Pig – Cthulu Larva
March of the Sea Pigs
Sea Pig Pictures
– Credit and Resource –
Hansen, B. (1972). “Photographic evidence of a unique type of walking in deep-sea holothurians”. Deep Sea Research and Oceanographic Abstracts 19 (6): 461–462. doi:10.1016/0011-7471(72)90056-3.
Miller, R. J.; Smith, C. R.; Demaster, D. J.; Fornes, W. L. (2000). “Feeding selectivity and rapid particle processing by deep-sea megafaunal deposit feeders: A 234Th tracer approach”. Journal of Marine Research 58 (4): 653. doi:10.1357/002224000321511061.
“Scotoplanes globosa (Sea Pig).” Encyclopedia of Life. Accessed June 9, 2014 at http://eol.org/pages/599675/overview.