Sea Spiders

There is a group of (often) eight-legged animals living in many of the world’s oceans, and while they might resemble our web-building friends, sea spiders are not arachnids at all.

Photo: Steve Childs

Unlike the terrestrial spiders they resemble, sea spiders can have up to twelve legs, though eight is more common. They have very thin bodies and thus have no need for a respiratory system, instead breathing through a process called diffusion.

Sea spiders can grow quite large, with some reaching diameters of up to three feet; however, most are much smaller. These animals are capable of either swimming or walking on the sea floor and spend their days hunting or scavenging for sea life such as sea-anemones and sponges.