Also known as starfish, the more than 2,000 species of sea stars are found throughout the world's oceans. They live in a variety of ocean habitats, including bay bottoms, dock pilings, rocky shores, tide pools, cold seafloors and warm tropical waters.
Found in a variety of colors, sea stars are unique in that they have no brains or blood. With a nervous system spread through their arms, sea stars are able to regenerate a new body from just a portion of a severed limb. Bony, calcified skin protects these echinoderms from predators, while they use tube feet to pry open the shells of clams and oysters.