| Killer Whale (Orcinus
orca)
Orcas frolick off
Victoria, with the Olympic Mountains of Washington State as a backdrop |
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 1970s, 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, mainly
salmon. 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 | 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 |
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 in the fall by the same route 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 1900s, but have recovered
well since their hunting was banned in 1947. Whale watching expeditions are available
from the west coast of Vancouver Island. |
Annual Calendar of the Gray Whale: |  | January
and February: Gray Whales spend the winter in the warm waters off Baja California,
Mexico. |  | March,
April, and May: They migrate north, hugging the west coast of North America. |  | June
to October: In the Bering and Chukchi Seas, the whales spend the summer feeding.
To the delight of Vancouver Island whale watchers, some grays stop to eat at this
latitude instead of continuing north with the rest of the population. |  | November
and December: Grays swim back down to Baja California, usually faster and further
offshore than during the northward leg of their migration. |  | In
total, the 16,000 to 22,500-km round trip - depending on how far north they go
- is one of the longest migrations of any mammal on earth. |
Humpback
Whale (Megaptera novaeangliae)
Humpback Whale
Tail | 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 whales, about 2,000 inhabit the north Pacific
Ocean. 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. |