About Sea Spiders

Appearance

• Sea spiders have very long and slender legs. The number of legs each spider has depends on the species. Some sea spiders have three pairs of legs, while others have four or even five pairs. Sea spiders have extremely small abdomens, which often appear as if they have not fully developed. The head of a sea spider features a proboscis, which is how the creature eats. A proboscis is a long, tube-like mouth part that is designed for sucking up food items. Sea spiders can grow to between 1/100 of an inch to about 20 inches across.

Diet

• Sea spiders are carnivorous. Their diet depends on the species, size of the spider and habitat. They most often eat soft-bodied invertebrates, such as nudibranchs, or very small crustaceans. Sea spiders use their proboscis to either suck the essential nutrients from the prey, or bite away pieces of meat. According to the University of California, some larval sea spiders spend a part of their lives as parasites, attaching themselves to invertebrates and feeding off of them.

Habitat

• Sea spiders can be found in nearly every part of every ocean. They are most common in the Mediterranean and Caribbean seas, as well as the Antarctic and Arctic oceans. Many types of sea spiders prefer somewhat shallow waters, but some species live in much deeper water. Sea spiders that live deep in the ocean are often much larger than their shallow-water counterparts. The largest sea spiders are found in the Antarctic ocean.

Life Cycle

• Little is known about how sea spiders reproduce and mature, or about how long they live. Because of their usually small size and extremely slow movements, they blend into their surroundings and are often overlooked by researchers or divers. It is believed that the male sea spider cares for the young until they have passed through the life stage where spiders gain their second or third pair of legs. It is assumed that sea spiders molt, shedding their exoskeleton, much as land spiders do, as they grow.