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Range and Habitat: Coastal areas of all oceans except
the central and eastern Pacific, and central Indian oceans; often
found in shallow waters. They inhabit temperate and tropical waters,
and are bottom and surface dwellers. They may be found as deep
as 1,200 meters from surfline to basin, but they are mainly a
coastal species. It is a migratory species, common in shore waters
during the summer and moving southward or to deeper waters in
the winter. It is most active at night.
Description: The longest recorded Sandtiger shark was
3.18 meters (about 11feet). Sandtiger sharks usually range from
2-3 meters (4-8 feet), however females are often a bit larger
than males. Adult sandtiger sharks have hunch backs, narrow snouts,
golden-brown sheen to the skin (some have large reddish or brownish
spots scattered on their bodies). They also have short gill openings.
Habits and Adaptations: Awl-shaped, dagger-like pointed
teeth (narrow double-edged teeth without serrations--excellent
for grasping and eating prey whole), ferocious appearance (toothy
grin), fairly large eyes. Sandtiger sharks often feed cooperatively,
which makes them socially unique among sharks. They are often
found in groups of a few dozen, hovering in caves or near shipwrecks.
This shark has an interesting method of buyoancy control -- it
has been seen swallowing air at the surface and holding it in
its stomach to maintain neutral buyoancy. Sandtiger sharks are
a migratory species, common in inshore waters during the summer
and moving southward or to deeper waters in winter. They are most
active at night.
Diet: Bony fish, small sharks and rays, cephalopods and
large crustaceans; feed voraciously on small fish at night.
Breeding and Maturation: Females usually stay in localized
areas, while males migrate more. They are ovoviviparous. This
species of shark is unique because of the intra-uterine cannibalism
that occurs. Only one embryo per uterus survives. Size at birth
is more than 3 feet. These young are born with sharp, functional
teeth. Lifespan is unknown.
Miscellaneous: Sandtiger sharks are ideal for underwater
shark-watching tours, as well as for exhibit purposes, due to
their hardiness, tendancy to swim slowly, and their constant display
of teeth. In the 1960s these sharks were almost wiped out due
to spearfishing, over-collecting, being fished for their livers
which are rich in vitamin A, and for sharkfin soup. Sandtigers
swallow air to achieve neutral buoyancy, maintaining their position
in the water without actually swimming. They are also able to
switch from respiratory pumping (at rest) to ram-jet ventilation
(open mouth swimming at high speeds) and save energy. These sharks
are considered somewhat dangerous, however in the U.S. there are
no reported cases of unprovoked attacks by this species of shark.
They sometimes steal spearfisher’s catches, and if these
spearfishers defend their catch they could be attacked. Sandtigers
are still trophy hunted for jaws, liver and valuable flesh. Their
only predator is humans. Australians call them ‘Grey Nurse
Sharks;’ South Africans call them ‘Ragged Tooth Sharks.’
They are related to smalltooth sandtigers and bigeye sandtigers,
which are found in deeper waters.
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