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Carcharias taurus.
a) Side view, b) head profile, c) underside (juvenile male), d) nose valve,
e) upper and lower left row of teeth
© D. Weber
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The sand tiger shark (Carcharias taurus) is one species of shark which has been chased and
slaughtered simply because of its threatening appearance. This harmless species has been
practically extinguished in individual regions of the world and it remains to be seen if the
protective measures introduced in several countries will prove to be effective.
Every year sand tiger sharks undertake long migrations. This means they always appear
seasonally - normally within a specific time period of several weeks - at the same places.
Their ocean habitat ranges to a depth of approximately 200 meters and they are usually
nocturnal. Based on current knowledge, the sand tiger shark is the only shark species which
swims to the water's surface and swallows air in order to regulate its buoyancy, enabling the
animal to move around and remain at any desired depth. Although they are very strong, they
appear lethargic and tend to swim slowly.
The physical appearance of a sand tiger shark strongly reflects the many prejudices which
people tend to have about sharks: large, with permanently visible, long and dagger-formed
teeth. In reality, however, sand tiger sharks are completely harmless. They have extremely
small eyes but no Nickhaut (a third eyelid which it can pull over its eyes, a feature found, e.g.
with gray sharks). In addition to its prominent teeth, its equally sized dorsal finds are
considered another typical feature. Sand tiger sharks are light brown in color, with bronze-
colored backs, a white abdomen and very often red spots on its flanks.
Sand tiger sharks can grow to a length of more than 300 cm. Males and females are sexually
mature when they reach a length of approximately 220 cm. Juveniles are born alive and
measure approximately 100 cm in length at birth.
Sand tiger sharks prefer to feed on fish such as herring, snappers/Schnapper, eels,
mackerels or other fish, and in rare cases, some smaller shark species. According to reports
this species also goes hunting together, driving together swarms of fish and thus making
them easy prey.
The sand tiger shark has an unusual method of reproduction. During its embryonal phase,
the more developed embryos eat up their less developed siblings. In this way only the two
strongest young - one per uterus - survive and are born. At birth they measure one meter in
length, which considerably increases their chances of survival since it reduces the number of
their natural enemies. A similar strategy can be found with other shark species, whereby the
embryos are not cannabilistic, but rather feed on less developed eggs found in the uterus.
However, such strategies are only common with shark species who have no real uterus, for
these would otherwise provide for a constant food supply. The length of gestation with sand
tiger sharks is between 8 to 12 months.
Sand tiger sharks are found practically around the world in regions with moderate climates.
They live in the western Atlantic from Maine to the Gulf of Mexico, but are not found in the
Caribbean waters, although occasionally they are spotted around the Bahamas. Further
territories include southern Brazil to Argentina, Bermuda, the Canary Islands and the
Mediterranean. Around the African continent they are found mostly in South Africa and the
Red Sea as well as Australia and Tasmania.
Sand tiger sharks are often found in large groups which gather to mate or go hunting. Latest
observations show that sand tiger sharks display a distinct social behavior. They like to linger
socially underneath cliff overhangs or similar structures, remaining there motionless - with
the help of swallowed air - for longer periods of time.
Despite their frightening appearance, sand tiger sharks are harmless animals which divers
can get close to without hesitation. If one approaches them too closely they swim a couple of
meters away and then stop. Since sand tiger sharks are very shy, their populations have
been rapidly decimated as the first wave of "shark hysteria" hit humans. Especially in
Australia this once led to an alarming reduction of their populations, while today they are
protected.
May be published only by indicating the source: Shark Info / Dr. Erich K. Ritter
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