12 Bizarre Deep Sea Creatures

9. The Sea Pig: Enigmatic Wanderers of the Abyssal Plains

Scientifically called Scotoplanes globosa, the sea pig is an intriguing member of the holothurian family—more usually known as sea cucumbers. Though they have a porcine name, these odd animals have little in common with their terrestrial cousins. Rather, their unusual and even humorous look has captivated both public and deep-sea experts' curiosity. Usually at depths more than 1,000 meters, sea pigs are found only in the abyssal plains of the world's seas and are vital members of the ecosystem of these huge underwater deserts. The sea pig's translucent, pinkish body is most remarkable; it really looks like a "bloated, water-filled sausage" as some viewers have observed. Though most specimens are quite smaller, its gelatinous body can stretch up to 15 centimetres (6 inches). An internal calcium carbonate skeleton supports the sea pig's body, giving it rigidity while nevertheless allowing the flexibility required for living in the deep sea. Their skin's transparency is a result of adaptation to their deep-sea habitat, where it helps them to blend in with the surrounding darkness, therefore avoiding predators. Sea pig anatomy is fascinating in part because of its many tube feet, which stretch from many areas of their body—including their skull. Mostly helping with mobility on the seafloor, these tube feet have several uses. Using these appendages to "walk," or glide across the abyssal plains, the sea pig leaves distinct tracks seen in deep-sea images and movies. In an environment where nutrients are sometimes limited, sea pigs' special form of mobility enables them to cover somewhat vast distances in search of food, a necessary adaptation. As deposit feeders, sea pigs consume organic material dropped to the ocean floor, therefore supporting the deep-sea environment. Their nutrition mostly comprises of detritus, or broken down plant and animal waste that settles from oceanic top levels. Deep sea life depends critically on this substance, known as marine snow, which is Using their tube feet and tentacles around their mouth, sea pigs sort through the silt to remove organic particles and germs. Along with giving the sea pigs food, this feeding pattern aids in nutrient recycling and preserves the health of the abyssal ecology. Sea pigs exhibit among their most amazing actions a propensity to assemble in huge numbers—sometimes hundreds—in response to stimuli. These aggregations are believed to be connected to feeding possibilities, maybe resulting from the arrival of a particularly abundant source of organic matter, such a whale corpse, on the seafloor. Surprising for such apparently basic animals, the capacity of sea pigs to identify and react to such food reveals a degree of sensory acuity and behavioural complexity. Because of the difficulties in researching these deep-water residents, reproduction in sea pigs is still such a mystery. They are thought to reproduce sexually, releasing eggs and sperm into the water column where fertilisation takes place, much as other sea cucumbers. After drifting with ocean currents, the resultant larvae would settle on the seafloor and change into young sea pigs. Still under active study, though, are the details of their reproductive cycle—including frequency and triggers for spawning occurrences. Our knowledge of deep-sea ecology and the effects of human activity on these far-off habitats depends much on our study of sea pigs and other deep-sea holothurians. Growing interest in deep-sea mining and other resource extraction projects raises questions regarding possible consequences for abyssal plain fauna, especially sea pig numbers. These organisms could be indicator species for the state of deep-sea ecosystems of their vital part in nutrient cycle and sediment processing. In biomedicine, marine pigs have also drawn interest. Like many echinoderms, they have amazing regeneration capacity and can grow missing body parts. Researchers have looked at sea pigs and related species for possible uses in regenerative medicine and the creation of new biomaterials based on their regenerative capacity and special biochemical adaptations allowing them to survive in the extreme conditions of the deep sea. Our knowledge of sea pigs and their function in deep-sea ecosystems keeps developing as technology develops and makes more thorough views of life in the abyss possible. Reminding us of the great variety of life on our planet and the need of conserving these special habitats for next generations, these strange but intriguing animals act as champions for the many undiscovered species that call the great, uncharted territories of the deep ocean home.