Blue sharks can reach lengths up to 3.8 m. Average-sized sharks are smaller, more like 1.8 to 2.4 m. A blue shark can weigh up to 200 kg. Pups are 48 cm long at birth.
Blue sharks eat almost anything. They eat fish and squid. But they also eat small sharks, seabirds, and garbage.
They are eaten by bonito sharks and other large sharks. The California sea lion has been seen eat by blue shark.
Blue sharks live in temperate and subtropical waters. They are found at the surface down to 350 m.