Scientifically known as Prionace glauca, a blue shark is a fish that lives in sub-tropical and tropical waters. A blue shark can weigh up to 450 pounds (200 kg) and grow to around 12.5 feet (7 m) long. Its name is derived from its coloring, which is a deep blue on the topside of the body, a lighter blue on the sides, and white on the belly. These sharks are related to other well-known sharks, such as the bull shark and tiger shark. Occasionally, a blue shark will approach a shore close enough to be seen by divers.
Besides the blue coloring of this shark, its appearance is distinct from other sharks in its family. These sharks have a relatively slender body with comparatively long fins growing from their sides and pointing downward from the body. Sexually mature female blue sharks can be identified by the scars around their neck, as male sharks bite during mating sessions. Due to this, they have developed skin much thicker than a male blue shark.
Blue sharks are nicknamed the wolves of the sea because of their habit of swimming in groups called schools. The schools are commonly organized by size and gender. They primarily hunt squid, but will go after octopuses, smaller sharks, and lobsters. Flesh of much larger animals, such as whales, is occasionally found in the stomach of blue sharks when they are captured.
Swimmers and divers have little to fear from a blue shark because this type of shark is rarely curious or aggressive enough to approach. Less than 50 blue shark attacks on people were recorded from the years 1580 to 2008, with roughly half of the attacks classified as provoked. Shark attacks are more common with the blue shark’s relatives: the tiger and the bull shark. Still, any kind of shark should not be approached due to sharks' potential to cause massive injuries and death.
While many types of sharks are regularly kept in large aquariums, this particular species of shark is rarely among them. These sharks have difficulty avoiding walls and normally die within one month of being caught and placed into an aquarium. There is at least one well-documented, somewhat successful attempt at keeping a blue shark alive in an aquarium, but the keepers loosed bull sharks and lemon sharks into the tank believing the species would get along. The bull sharks preyed on the blue sharks, however.