The term “sand shark” often refers to the sand tiger shark (Carcharias taurus), a species found in temperate and subtropical waters globally. These sharks are known for their distinctive appearance and generally placid nature, despite their intimidating teeth. This article explores their characteristics and their relationship with humans.
Identifying Sand Sharks
Sand tiger sharks possess a stout, bulky body, typically brownish-grey on their upper side with a paler underside. Many individuals display scattered reddish or brownish spots, particularly on their rear body, which tend to fade as they mature. They can reach lengths of up to 3.2 meters (10.5 feet), though most specimens are between 2.2 and 2.5 meters long, weighing up to 159 kg (350 pounds).
A prominent feature is their flattened, conical snout and a mouth that extends behind their small eyes. Their mouth often remains open, revealing three rows of long, narrow, and sharp teeth. These teeth have smooth edges with one or two smaller cusplets on each side, designed for impaling prey rather than tearing. Sand tiger sharks also have two dorsal fins of similar size, set back on their body, and a distinct caudal fin with an elongated upper lobe.
Habitat and Diet
Sand tiger sharks inhabit continental shelf areas in subtropical and temperate waters worldwide. They are commonly found in sandy coastal waters, estuaries, shallow bays, and around rocky or coral reefs, typically at depths up to 191 meters (627 feet). While they often stay near the bottom, they can also be observed throughout the water column.
These sharks are primarily nocturnal hunters. Their diet mainly consists of bony fish, making up about 60% of their food intake. They also consume crustaceans, squid, skates, and smaller sharks. Sand tiger sharks employ a unique hunting strategy: they can gulp air from the surface and store it in their stomach, allowing them to achieve near-neutral buoyancy and hover motionlessly in the water, aiding stealthy approaches to prey. Groups of sand tiger sharks have also been observed cooperatively herding large schools of fish.
Behavior and Interaction with Humans
Despite their formidable appearance and rows of visible, sharp teeth, sand tiger sharks are generally considered placid and slow-moving. They are not typically aggressive towards humans unless provoked. The International Shark Attack File lists 36 unprovoked, non-fatal attacks attributed to sand tiger sharks, with no confirmed human fatalities.
While mostly solitary, sand tiger sharks can aggregate in groups for feeding, mating, or giving birth. Their tendency to frequent shallow coastal waters means they can come into proximity with humans. Experts advise treating them with respect due to their size and teeth, and caution is warranted if spearfishing, as they have been known to bite at speared fish. Their non-aggressive nature, combined with their imposing appearance, makes them a popular species in public aquariums.
Conservation and Common Misconceptions
The term “sand shark” often refers to the sand tiger shark (Carcharias taurus), distinct from other species sometimes called “sand sharks” or the unrelated tiger shark (Galeocerdo cuvier). Other common names include grey nurse shark (Australia) and spotted ragged-tooth shark (South Africa).
Globally, the sand tiger shark is listed as “Vulnerable” by the International Union for Conservation of Nature (IUCN). In some regions, such as the western Mediterranean, Europe, and eastern Australia, they are classified as “Critically Endangered.” Their population decline is largely due to overfishing for their meat, fins, and oil, as well as bycatch. Their slow reproductive rate, with females giving birth to only one or two pups every two to three years, makes them susceptible to population reduction and hinders recovery efforts. Sand tiger sharks also face threats from habitat loss and degradation in their coastal environments.