Killer whales are found in all oceans, but are never abundant. Sightings in
the
northwest Atlantic have been reported from the ice edge south to the
Caribbean.
They seem to prefer coastal areas and can sometimes be seen in
bays. Movements
in the northwest Atlantic are poorly understood but
probably correspond with
that of their prey. Sightings in Newfoundland and
Labrador waters are most
frequent in summer, although they are known to be
present year-round.
By photographing the greyish "saddle patch" behind the dorsal
fin, individual
whales can be recognized. On the west coast of Canada, a
catalogue of such
photos has allowed scientists to follow and study groups
of killer whales for years.
Little work on killer whales has been carried
out in Newfoundland waters.
Killer whales may live for up to 35 years. At the end of a year-long
pregnancy,
a 3 m calf weighing 400 lbs. is born, and is nursed for one
year. Males reach
maturity at a length of 6 m, and females at 5 m. Males
are generally larger than
females, and can be up to 10 m long and weigh 8
tons. Females do not exceed
8.5 m in length. Males have a tall, straight
dorsal fin, while that of the female is
smaller and hooked.
The basic social unit appears to be an extended family consisting mainly of
related females, with about 20 percent males. Such groups remain together for
life and travel as a cohesive unit. Vocalizations consist of a wide variety of
whistles,
and there is evidence that different groups are recognizable by
their unique
dialects. Killer whales feed on fish, squid, seabirds, and
other marine mammals.
They are known to hunt cooperatively, in a manner
reminiscent of wolves on
land. Smaller prey can be swallowed whole, while
larger animals such as other
whales must be torn apart. Each day they eat
about 4% of their body weight.
Killer whales are a popular topic of many legends, and are prime
attractions
in some marine parks. Although great ferocity is often
attributed to them, there
is little evidence that they pose a threat to
man, any more than other large, wild
animals.
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