Their cigar-shaped bodies are well suited for swimming. Two fins help to stabilize or balance t he body when swimming, and the internal shell, called a pen, gives support to the muscular mantle. Squids can cruise along at constant speeds or dart about in quick jerky movements. Squids have ten arms, two of which are called tentacles. The tentacles are longer than the arms and have flattened ends like a spatula.
Suckers are on the underside of all the arms and only on the flattened ends of the tentacles.
The tentacles are used fo r feeding. The suckers, which may have hooks, help capture small fish and shrimp, which are quickly torn apart by the beak. The quick moving squids are eaten by a variety of predators. The smaller species are food for sea otters, sea birds, large fish and humans. Their pale bodies can become almost transparent if necessary or take on the coloring of nearby rocks or seaweeds.