Meet the Sea Pig
Scotoplanes, commonly called the sea pig, is a genus of deep-sea sea cucumbers found on abyssal plains worldwide. The name is apt: these creatures are plump, pink, and walk on inflated tube feet that look disturbingly like legs. They are also among the most abundant large animals on the deep ocean floor — in some regions, sea pigs make up over 95% of the total animal biomass on the abyssal plain.
What Is a Sea Pig?
Sea pigs are holothurians — sea cucumbers — belonging to the order Elasipodida. Unlike shallow-water sea cucumbers, which are typically elongated and largely sedentary, Scotoplanes are mobile, semi-transparent, and equipped with enlarged, water-filled tube feet that they use to walk across the seafloor. Their bodies are typically 8–25 cm long and pale pink or white, with a translucent quality that makes their internal organs faintly visible.
They have antennae-like appendages on their backs that are thought to be sensory organs, detecting water currents and possibly chemical gradients. Their mouths face downward, optimized for sediment feeding.
How Sea Pigs Eat
Sea pigs are deposit feeders — they eat mud. More specifically, they ingest large quantities of seafloor sediment and extract the organic matter (bacteria, decomposed organic material, microscopic organisms) as it passes through their digestive system. They are essentially living vacuum cleaners of the abyss, processing enormous volumes of sediment as they move.
This feeding strategy makes them critical to deep-sea nutrient cycling. In regions with high sea pig populations, they process and redistribute a significant fraction of the organic material that sinks from the surface ocean — linking the productive surface waters to the abyssal food web.
The Herding Behavior
One of the most striking things about sea pigs is that they aggregate. ROV footage from abyssal plains has revealed groups of hundreds to thousands of sea pigs moving together across the seafloor. This herding behavior is thought to be related to food — sea pigs orient themselves facing into the current, which delivers fresh organic material settling from above. When a large food fall occurs (a whale carcass, for example), sea pigs can detect it chemically from kilometers away and converge in large numbers.
Where Do Sea Pigs Live?
Scotoplanes are found in all major ocean basins at depths of 1,000–5,000 meters — the abyssal plain zone. They are particularly abundant in the Pacific and Atlantic. Despite their abundance at depth, they are rarely encountered by humans because of the extreme depth and remoteness of their habitat.
Frequently Asked Questions
Is a sea pig a real animal?
Yes. Scotoplanes is a genus of deep-sea sea cucumbers found worldwide on abyssal plains. They are well-documented by deep-sea ROV expeditions.
Why is it called a sea pig?
Because of its plump, pinkish body and the way its inflated tube feet resemble stubby legs. The resemblance to a small pig is genuinely striking in photographs.