Sand Tiger SharkCarcharias taurus
These large Lamnidae sharks grow to around 10 feet long, and have rounded triangular fins except for their asymmetrical caudal fin with an enlarged top lobe. They are classically gray to light brown on top and light below, but are often scattered with darker reddish brown blotches also. They prefer hunting fish and invertebrates inshore near reefs, surf, and shallow bays, and migrate north-south with the seasonal temperature changes. Sand tiger sharks are believed to produce one or two pups every few years because of intrauterine cannibalism, where the largest pup eats the smaller ones before birth.
English language common names include sand tiger shark, grey nurse shark, ground shark, spotted raggedtooth shark, slender-tooth shark, spotted sandtiger shark and ground shark. Other common names are bacota (Spanish), pintado (Spanish), sarda (Spanish), cação-da-areia (Portuguese), mangona (Portuguese), tavrocarcharias (Greek), chien de mer (French), kalb, (Arabic), grauer sandhai (German), hietahai (Finnish), karish khol pari (Hebrew), oxhaj (Swedish), zandtijgerhaai (Dutch), peshkaqen i eger (Albanian), shirowani (Japanese) and spikkel-skeurtandhaai (Afrikaans).
Importance to HumansIn the North Pacific, northern Indian Ocean and off the tropical west coast of Africa, the sandtiger is commercially fished for food. The meat is utilized, fresh frozen and dried-salted, fins are sold in oriental markets for sharkfin soup and jaws and teeth are used for trophies and orniments. The sand tiger shark is not a commercially targeted species in North American waters, partially due to its protected status. In some instances in Australian waters the sand tiger had been killed by divers using underwater weapons since it is slow moving and approachable. This practice was banned in Australia in 1984. Sandtigers survive very well in aquariums and are a favorite because of their large size and fierce look. This shark also inhabits coastal waters and popular dive sites, such as shipwrecks, where they can be observed by recreational divers.
Danger to HumansUnderwater observations of this shark reveal that it is not aggressive unless provoked. Its size and jagged teeth demand respect and have given it an undeserved reputation as a maneater in Australia, where it is often confused with other species, mainly requiem sharks. It has been known to attack people when provoked, especially when they are spearfishing. There have been accounts of sandtigers stealing fish off stringers and spears underwater. In total there have been relatively few documented attacks on humans. ISAF records account for only 29 unprovoked attacks with two resulting in fatalities.
Currently sand tiger sharks are regulated in the commercial longline shark fishery on the east coast of the United States by the National Marine Fisheries Service where it is identified as a prohibited species. Any sand tiger caught must be immediately released with minimal harm to the shark. The World Conservation Union classifies the sandtiger as "Vulnerable", which means it faces a high risk of extinction in the wild in the medium term future. This is due to an observed, estimated, inferred or suspected reduction in the population of at least 20% over the last 10 years or three generations. Since the sand tiger’s reproductive rate is very low, only one or two pups per mature female every one or two years, the population needs to be closely monitored. Catch rates of populations in Australia and South Africa have shown declines due to commercial fishing, spearfishing and beach meshing. Even with status as a protected species, the recovery of the sandtiger shark off the coast of Australia has been very slow.
The IUCN is a global union of states, governmental agencies, and non-governmental organizations in a partnership that assesses the conservation status of species.
Geographical DistributionThe sand tiger shark can be found in most warm seas throughout the world except for the eastern Pacific. In the western Atlantic Ocean it ranges from the Gulf of Maine (U.S.) to Argentina and is commonly found in Cape Cod (U.S.) and Delaware Bay (U.S.) during the summer months. In the eastern Atlantic it can be found from the coast of Europe to North Africa and within the Mediterranean Sea. Its range also extends from Australia to Japan and in the waters off South Africa.
Commonly found inshore ranging in depths from 6 to 626 feet (1.8 to 191 m), the sand tiger shark’s range extends to a variety of areas including the surf zone, shallow bays, coral and rocky reefs and deeper areas around the outer continental shelves. C. taurus is often found on the bottom but can also be seen throughout the water column. The sandtiger is migratory within its region, moving poleward during the summer while making equatorial movements during the fall and winter months.
1. Dirst dorsal fin is back on body, closer to pelvic fins than to pectoral fins
2. First and second dorsal and anal fins nearly equal in size
3. Snout flattened, with long mouth extending behind eyes
The sand tiger shark is a large, bulky shark with a flattened conical snout and a long mouth that extends behind the eyes. The first dorsal fin is set back and is much closer to the pelvic fins than the pectoral fins. The anal and dorsal fins are large and broad-based and the second dorsal fin is almost the same size as the first dorsal. Gill slits are anterior to the origin of the pectoral fins in this species. The caudal fin of the sand tiger shark is asymmetrically shaped with a strongly pronounced upper lobe.
Coloration of the sand tiger shark is generally light brown or light greenish–gray above and grayish white below. Many individuals have darker reddish or brown spots scattered on the body.
The teeth of the sand tiger shark have prominent narrow cusps with lateral cusplets. The upper anterior teeth are separated by small intermediate teeth. The upper teeth number 44 to 48 and the lower teeth number 41 to 46. The teeth in the corners of the mouth are very small and numerous. The ragged looking teeth give the sand tiger shark a distinct menacing look.
Dermal denticles are loosely spaced and ovoid lanceolate shaped with three ridges. The axial ridge is prominent and sharp-edged anteriorly but usually is subdivided and flat-topped posteriorly. In individuals around 3.3 feet (100cm) long denticle sizes are about 0.016 inches (0.4mm) broad by 0.018 inches (0.45mm) long.
Size, Age, and Growth
Average size ranges from four to nine feet with maximum length believed to be around 10.5 feet (320 cm) in females and 9.9 feet (301 cm) in males. Male maturity is reached at 6.3 feet (190-195 cm) at four to five years of age. Female maturity is reached at six years or over 7.2 feet (220 cm) in total length. Individuals in aquariums have lived to be 16 years old.
The diet of this ravenous feeder mainly consists of a wide variety of small bony fish including herrings, bluefishes, flatfishes, eels, mullets, snappers, hakes, porgies, croakers, bonito, remoras, sea robins and sea basses. Other prey items of the sandtiger are rays, squids, crabs, lobsters and other smaller sharks. Cooperative feeding has been observed by schools of sharks surrounding and bunching schooling prey in order to feed on them.
Embryonic development is ovoviviparous with ovophagy and embryophagy occurring in the uteri. Usually only one pup survives in each uteri since the largest embryo ends up eating all of its smaller siblings during gestation. This generally limits litter sizes to two individuals. At 6.7 inches (17 cm) embryos have functional teeth and are feeding and at 10.2 inches (26 cm) they are able to move in utero. Gestation periods are believed to be around eight to nine months long and pups generally measure 39 inches (99 cm) at birth.
Juveniles are susceptible to predation by larger sharks. Mature individuals have no major predators.
Since the sand tiger shark is denser than water and lacks a swim bladder like bony fish, it has adopted a behavior that allows it to become neutrally buoyant in the water column. The shark comes to the surface and gulps air, which it holds in its stomach. This allows the shark to hover motionless in the water.
The sand tiger shark was originally named Carcharias taurus by Rafinesque in 1810. Since then it has also been referred to literature as Odontaspis taurus Rafinesque 1810, Eugomphodus taurus Rafinesque 1810, Odontaspis americanus Mitchill 1815, Squalus americanus Mitchill 1815, Carcharias griseus Ayres 1843, Odontaspis arenarius Ogilby 1911, Carcharias arenarius Ogilby 1911, Odontaspis platensis Lahille 1928, and Carcharius platensisLahille 1928.
Prepared by: Peter Cooper