How Sea Stars Thrive Without Blood Or A Brain
A Body Built Differently: Sea stars, often called starfish, are very different from humans and most animals people are familiar with. They do not have blood, and they do not have a brain. Yet they survive, move, eat, and sense their surroundings with great efficiency. Instead of blood, sea stars rely on seawater to move nutrients and oxygen through their bodies. Instead of a brain, they use a network of nerves that spread throughout each arm.