Sea Pig One of the Ugliest Sea Creature
The "sea pig" is the common name (i.e. non-scientific name) for a species of sea cucumber (in the class Holothuroidea) that lives in the deepest abyssal depths of the world's oceans.
Specifically sea pigs belong to the genus Scotoplanes, a genus of deep-sea sea cucumber which currently includes four species. Sometimes other genera of deep-sea sea-cucumbers are called "sea pigs", but historically, THIS is the one most people mean. Its not entirely clear if those four species are all distinct, but THAT is a discussion for another day...
The name Scotoplanes has been around for a LONG time. The genus was discovered and described by H. Theel in 1882 as part of the famous HMS Challenger expedition reports. Sea pigs are ELASIOPODID sea cucumbers, an order of sea cucumbers whose members are prominent in the deep-sea.
They are often characterized by having these little legs that come off the bottom surface such as what you see here (legs on side, mouth pointing outwards)
One species, Scotoplanes globosa seems to be particularly widespread with a distribution that is WORLDWIDE. Yup. That's right you can find it in the Atlantic, the Pacific, in the Indian Ocean and of course..in the Southern Ocean (Antarctica).
Because waters in the Southern Ocean (Antarctica) are so cold, sea pigs can be found in shallower waters around the South Pole. Pictured here is one collected during the recent expedition operated by the New Zealanders and held by NIWA scientist (and friend of the Echinoblog) Sadie Mills:
How do Sea Pigs Live ???
Scotoplanes live in the ABYSS. That's not just a little deep..that's the DEEPEST part of the ocean on the flat oceanic plains. Its not unusual for sea pigs to be collected from over 6000 meters!!! How deep is that? That's about 3.7 miles DOWN (by contrast the Grand Canyon at its deepest point is only about 1.1 miles deep). Some can be found shallower..but they live across a wide bathymetric range.Scotoplanes don't just occur individually either. Collections and observations of these animals show that they often number in the hundreds. Early trawling records have recorded some 300-600 specimens per trawl!!!
What do they do down there??
Very little is known about Scotoplanes general biology, but we do know a thing or two about their nutriton.Like a lot of other deep-sea sea cucumbers, Sea pigs are what's called deposit or detrital feeders. That is, they feed on the fine nutritious scum and goo that falls to the bottom of the seafloor from the top of the ocean. They feed on them with the ring of tentacles that surrounds the mouth...
BUT contrary to some accounts that these are "slug like" or coarse dirt worms, deep-sea cukes like Scotoplanes have evolved this feeding mode into a finely honed adaptation!!
For instance, this study by Robert Miller et al. (2000) studied several deep-sea cuke species from the North Pacific, including Scotoplanes globosa using isotope tracers.
S. globosa (and other species in the region) ingests only VERY fresh (and presumably very rich) food-rich sediments. This species (and others like it) feed on a thin veneer of food that had settled out of the water column the last 100 days. So they actually eat FRESH food.
Sea Pig One of the Ugliest Sea Creature video