A sea star is a marine animal with arms radiating from a central body, creating a star shape. Most sea stars have five arms, though some species have many more. These fascinating creatures live on the ocean floor, from shallow tide pools to the deep sea.

Sea stars are often called starfish, but they're not fish at all. They lack fins, gills, and scales. Instead, they belong to a group called echinoderms, which also includes sea urchins and sand dollars. Their bodies have a remarkable symmetry: if you drew lines through their center, each arm would mirror the others.

These animals move using hundreds of tiny tube feet on their undersides, creating a slow, gliding motion across rocks and sand. Sea stars are skilled hunters despite their sluggish pace. They eat mussels, clams, and oysters by prying open the shells with their strong arms, then pushing their stomachs out through their mouths to digest the prey outside their bodies.

Perhaps most amazingly, sea stars can regrow lost arms. If a predator bites off an arm, the sea star grows a new one over time. Some species can even regenerate an entire new body from a single severed arm. This remarkable ability to heal and rebuild makes sea stars one of nature's most resilient creatures.