Any of various sharks of the family Lamnidae, including the great white shark, mako, and porbeagle, having a pointed snout, a nearly symmetrical tail, and a reputation for aggressiveness. Any of several temperate-water sharks (genus Lamna) in a family (Isuridae) that also includes the great white shark and the mako shark group. The swift, active mackerel sharks have a crescent-shaped tail and slender teeth. They are gray or blue-gray above and paler below and about 10 ft (3 m) long. They eat fishes such as herring, mackerel, and salmon, sometimes taking fishermen's catches and damaging nets. They are fished commercially for food. Common species include the Atlantic mackerel shark, or porbeagle (L. nasus), and the Pacific mackerel shark, or salmon shark (L ditropis)