Spotted Ragged-Tooth Shark
The spotted ragged-tooth shark (Carcharias taurus) is also called the sand tiger shark, grey nurse shark or blue nurse sand tiger and inhabits subtropical and temperate waters worldwide. It lives along the continental shelf from sandy shores (hence the name sand tiger) and reefs to a depth of around 190 metres. They are found off Japan, Australia, South Africa, the Mediterranean and east coasts of North and South America. They are not related to the tiger shark but are a distant cousin of the great white shark.
Adult sharks range from 2 to 3.2 metres in length and weigh from 91 to 159 kg in weight.
The head is pointy, while the snout is flattened with a conical shape. Its body is stout and bulky with its mouth extending beyond the eyes. They normally swim with their mouths open displaying three rows of protruding, smooth-edged, sharp-pointed teeth. The caudal fin is elongated with a longer upper lobe and they have two large, broad-based dorsal fins set back beyond the pectoral fins. Adults tend to have reddish brown spots.
These sharks in South Africa undertake an annual migration and pup during the summer in the cooler waters after which they move northwards toward sites where there are suitable rocks and caves where they mate at night during and just after the winter. After mating the swim further north to warmer waters where gestation takes place. They then return again in the autumn to the south to give birth in the cooler waters.
Despite its fearsome appearance and strong swimming ability, it is a placid and slow-moving shark with no confirmed human fatalities. They mainly feed on the bottom and their diet consists of bony fish, crustaceans, squid, skates and other sharks. It is the only shark that gulps air and store's it in its stomach to maintain neutral buoyancy which helps it to hunt motionless and quietly
The greatest threat to the ragged-tooth shark is over fishing due to the fact that they reproduce at an unusually slow rate and breed only every second or third year. In the western northern Pacific, off Ghana, India and Pakistan it is a highly prized food source; in Japan they are caught for their fins; in North America they are fished for the hides and fins; in South Africa and some other countries they are sought after prizes in fishing competitions and shark liver oil is a popular product for cosmetics like lipstick. The species is therefore listed as vulnerable.