The Blue Shark (Prionace glauca) is a sleek, slender, fast-swimming shark. It has blue skin, 5 gill slits, two dorsal fins, an anal fin, no fin spines, and nictitating eyelids (which protect the eyes when the shark is hunting). Its elongated caudal fin (tail) provides swimming power as it moves side-to-side. Blue Sharks grow to be up to 12.5 feet (3.8 m) long. The Blue Shark is found worldwide, but is endangered due to over-fishing.

Teeth and Diet: The Blue Shark's teeth are pointed and serrated. This enables the shark to catch slippery squid and fish, the mainstay of this carnivore's diet.

Classification: Kingdom Animalia, Phylum Chordata, Class Chondrichthyes, Order Carcharhiniformes, Family Carcharhinidae, Genus Prionace, Species glauca.