The grey reef shark is a fairly small species of shark with a long, streamlined body. It is a common species, living in the coastal regions of the Pacific and Indian Oceans. With its long streamlined body, it glides smoothly through shallow areas and reefs. Although small, growing to a maximum of about 7 feet (2.13 m), it can have quite an aggressive nature.
Grey reef sharks are part of a family of similar reef shark species. These include the Caribbean reef shark, the black-tipped reef shark, and the white-tipped reef shark. They all have the typical slender gray body, white under belly, large eyes, and broad, rounded nose. Unlike their cousins, the grey reef shark's first dorsal fin is often tipped with white, and the the rear edge of the tail fin has a broad black stripe. The shark's second dorsal fin, pectoral fins, and pelvic fin have blackish-brown edges.
The diet of the grey reef shark consists primarily of cephalopods such as squid, shrimp, and octopi, and fish. They are nocturnal and typically hunt at night. Reef sharks are social creatures and when not hunting, they spend their time congregated in groups of up to 20 other sharks. They also often lay motionless on the ocean floor. These sharks have a very strong sense of smell, and are able to detect the presence of prey or danger at great distances.
A female grey reef shark gives birth to up to six fully developed pups every two years. The gestation period is about 12 months. Pups are typically around 2 feet (60.96 cm) long at birth and mature in about seven years. These sharks can live to be 25 years old.
The grey reef shark has very few natural enemies, since it tends to stay in the shallower waters. Despite its small size, its aggressive nature allows it to drive off other sharks and predators and claim territories for themselves. When threatened, the shark arches its back and swings it head from side to side. This apparently aggressive behavior is thought to be an attempt to intimidate or scare off predators. Although rare, attacks on humans by the grey reef shark have been reported. More often, this type of shark is simply curious and may approach undersea divers to investigate.