The Sand Tiger Shark (Carcharias taurus), grey nurse shark, spotted ragged tooth shark, or blue-nurse sand tiger is a species of shark. The sand tiger is categorized as vulnerable on the International Union for Conservation of Nature Red List. It is the most widely kept shark in public aquariums owing to its large size and tolerance for captivity.
The eyes of the sand tiger shark are small, lacking eyelids, one of the shark's many distinct characteristics. The head is rather pointy, as opposed to round, while the snout is flattened with a conical shape. Its body is stout and bulky and its mouth extends beyond the eyes. The sand tiger shark usually swims with its mouth open displaying three rows of protruding, smooth-edged, sharp-pointed teeth. Adult sharks tend to have reddish-brown spots scattered around their entire body. Juvenile sand tiger sharks have yellow-brown spots on their bodies. The sand tiger shark has a grey back and white underside. The males have grey claspers with white tips located on the underside of their body. The caudal fin is elongated and has a long upper lobe. They have two large, broad-based grey dorsal fins set back beyond the pectoral fins. The pectoral fins are triangular, and the tail is almost one-third as long as the shark's head. The sand tiger's length at sexual maturity averages 1.9 to 1.95 m (6.2 to 6.4 ft) in males and 2.2 m (7.2 ft) in females, the latter being the larger-bodied sex. Large mature specimens can attain a length of 3.0 to 3.4 meters (9.8 to 11.2 ft). A specimen of 50 kg (110 lb) in weight is considered "medium"-sized while a 95 to 110 kg (210 to 240 lb) specimen is considered "average"-sized. Sand tiger sharks have been reported to attain a maximum mass of 159 kg (350 lb), however some sources claim the specimen can attain a weight of 300 kg (660 lb).
Sand tiger sharks roam the epipelagic and mesopelagic part of the ocean, sandy coastal waters, estuaries, shallow bays, and rocky or tropical reefs, at depths of up to 19 meters (62 ft). However, sand tiger sharks inhabiting even deeper depths have been recorded.
The diet of the sand tiger shark often consists of fish, young sharks, rays,crustaceans, and bluefin tuna trapped in nets. The sand tiger hunts a variety of fish along the Atlantic coast of North America, including mackerel, menhaden, butterfish, flounder, weakfish, bonito, alewives, and silver hake. However, the sand tiger prefers bony fish such as eels, mullets, and sea basses.
The sand tiger shark is an active night feeder. It is the only shark known to gulp air and store it in the shark's stomach, allowing the shark to maintain near-neutral buoyancy which helps it to hunt motionlessly and quietly so as not to alert its prey. The sand tiger shark has been observed to gather in hunting groups with other sand tiger sharks when preying upon large schools of fish. The sand tiger shark also gathers in numbers when hunting large prey or when mating. As the shark matures, it tends to eat larger prey including other sharks, dolphins, and swordfish. Biologists have observed that the shark will usually swallow its prey whole, which if the prey is too large can lead to health problems for the shark such as esophagus, heart, and liver damage.