| Killer Whale
(Orcinus orca)
Orcas
frolick off Victoria, with the Olympic
Mountains of Washington State as a backdrop
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The Killer Whale
is, apart from humans, the most widespread mammal in the world. Still,
it is well known in only a few areas, and one of these is the coastal
waters of British Columbia. In the early 1970's, researchers developed
a system of photo-identifying individual whales, in order to better
understand their natural history, and monitor the population. Every
whale has identifying features on its dorsal fin, and the gray "saddle
patch" behind the dorsal fin, and an extensive catalogue of Orca
"mug shots" is now on file, each taken from the whale's
left side.
It was soon
learned that these animals have a well-established family structure,
travelling in groups called pods. Some of the pods lived in the
northern part of the Strait of Georgia (the "northern resident"
pods), and others remained in the southern half of the strait, and
the Strait of Juan de Fuca (the "southern residents").
It was also discovered that there were other pods that seemed to
move more randomly. They became known as the "transient"
whales. While they looked similar, it was learned that they fed
exclusively on marine mammals, while the resident whales appeared
to feed only on fish. A third group, which appears occasionally
off the west coast, is still poorly understood.Each pod is structured
around the oldest female, with males remaining in their mothers'
pods. These groups communicate vocally underwater, and each pod
uses a slightly different dialect.
Orca
Whales, Vancouver Island
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Because Killer
Whales have been identified individually for some years now, their
lives are becoming better known to marine biologists. The bulls
are larger, reaching a weight of 9,000 kilograms, and a length of
almost ten meters. A bull's dorsal fin may be almost six feet high.
Maturity may not be reached until the age of 15 to 20 years. Cows
are thought to live longer than the bulls, with average life expectancy
estimated to be 50 years. Some cows may be as old as 80 years of
age.
With well-understood
movements, the Killer Whale has become an extremely popular attraction
for British Columbia visitors. Many companies offer whale watching
cruises on Vancouver Island. As concern grows about the negative
effects of whale watching, these companies are working very hard
to self-monitor their activities. There is to date no evidence that
the whales are suffering because of humans' fascination with them.
Gray Whale
(Eschschrictius robustus)
Gray
Whale Tail
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Each spring,
some 20,000 Gray Whales move past the western shore of Vancouver
Island, en route to summer feeding grounds in the Bering Sea. The
30 ton giants can be seen from shore, as early as February, with
females and calves passing in April and early May. They return by
the same route in the fall, to their calving and wintering areas
in the lagoons of Baja California. Gray Whales belong to the family
known as baleen whales, which feed by straining huge mouths full
of sea-bottom mud through filter-like baleen plates.
Tiny marine organisms are thus captured by the baleen, and then
swallowed by the whale. These large and slow animals are often encrusted
with barnacles and other marine life, visible when they surface.
Gray Whales
were almost hunted to extinction in the early 1900's, but have recovered
well since their hunting was banned in 1947. Whale watching expeditions
are available from the west coast of Vancouver Island.
Humpback
Whale (Megaptera novaeangliae)
Humpback
Whale Tail
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The Humpback Whale
is one of the medium sized baleen whales. They are distinctive for
their long pectoral flukes, and pale undersides.
Of a global
population of some 10,000, about 2000 inhabit the north Pacific.
They breed in waters off Mexico and Hawaii, and migrate to the north
Pacific to feed in the summer. Like other baleen whales, Humpbacks
feed by sieving seawater through the fan-like baleen plates that
hang from the roofs of their mouths.
This species is unique in that several whales may create a ring
of bubbles called a "bubble-net", to concentrate small
fish and crustaceans into an area, so they can be more easily consumed.
These large whales can stay submerged for about thirty minutes,
but usually are down for shorter periods. On the surface, they engage
in spy-hopping, flipper-flapping, tail-slapping, and breaching.
Once quite common even in inshore waters, the Humpback Whale is
currently listed as threatened, and its numbers are recovering.
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