There is no shark more
notorious than the great white. Found in the warm temperate parts of
all oceans, this shark has been recorded in the Atlantic as far north
as Hare Bay, Newfoundland and the Gulf of St. Lawrence. Occasionally,
great white sharks have been reported in British Columbia waters and
even as far north as Alaska. In Canada, the great white appears in
warm waters, most frequently in August preferring the water
temperatures between 12 and 25°C.
Sharks are the modern survivors of an ancient group that was among
the first true fish to inhabit primeval seas. They differ from most
modern fish in that they have a skeleton of cartilage rather than of
bone. Absent also is the swim bladder that other fish have, which means
that sharks must move constantly or sink towards the bottom.
Although about 340 species of sharks have been catalogued worldwide
from the Arctic to the Antarctic, only 36 species occur in Canadian
waters. The great white is distinguished from the other related mackerel
sharks by its distinctive, strongly serrated, almost triangular-shaped
upper-jaw teeth which approach 8 cm in length. Its snout is conical and
pointed, hence the shark is sometimes called the white pointer.
Despite its name, the great white shark is not white at all, except
in very large specimens which are a dull white grey. The back is lead
grey, grey brown, slate blue or black and fades to a dirty white on the
belly. The pectoral fins (both sides) have black tips while the dorsal
(back) and caudal (tail) are dark along their rear edges.
The great white lives to be at least 20 years old, while growing to
be about six metres in length. Its diet consists of harbour seals, sea
lions, harbour porpoises, shell fish, sea turtles, gulls and fish. Many
unusual items have been found in the stomachs of these sharks including
a whole sheep, a bulldog, a cuckoo clock and bottles and cans.
San Diego Natural History Museum
Shark Research Program at the University of Florida Museum of Natural History
Australian Museum Online
Shark Images from Douglas J. Long
ReefQuest Expeditions
South African White Shark Research Institute
Pelagic Shark Research Foundation
Warbird
Grand Requin Blanc
École de Vaucresson
