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Orca Killer Whales, Gray Whales, Sea Lions
and other Marine Wildlife of the Pacific Northwest in the Gulf Islands
and the San Juan Islands including Victoria, Vancouver, Sooke,
Friday Harbor and Orcas Island.
The Killer Whale is the largest member of the
dolphin family and they tend to be found in groups called pods,
a group of related families. Occasionally two or more pods join
together temporarily and can consist of up to 100 whales. Each pod
has been named over the years by researchers.
Orcas vocalize while going about their various
activities. The clicks you hear in some of the audio files are the
sounds Orcas use to echo locate food and other underwater objects.
The other sounds are calls that the whales use to communicate with
each other.
The forehead (or melon of an Orca) is used to
generate the wide variety of sounds the whale is capable of producing.
Sounds are generated when the whale forces air in and out of the
complex network of passages and cavities in the melon.
Resident, transient, and offshore killer whales
have very different vocabularies. Both the sound of the calls and
the number of calls vary substantially from population to population.
Transient killer whales vocalize significantly
less than residents because they normally don't use sound while
foraging for food. Residents will send out calls to other residents
and use sonar clicks to locate their prey. Transients, on the other
hand, usually hunt silently, listening and looking for their prey.
It is speculated that the reason for this is that the dolphins,
porpoises, seals, and sea lions that constitute the transient's
primary prey could recognize transient calls and thereby rob the
transients of the advantage of surprise. Transients normally begin
to vocalize during or after an attack.
As you listen to the sound files below,
the differences between resident clans should become apparent. Note
how very different the sounds made by transient Orcas are from their
offshore and resident cousins. The sound files are in RealAudio®
format and require the latest version of RealPlayer™
There are three different populations of Orcas
encountered along the West coast of North America. These three groups
appear to be genetically different and do not interact socially--in
fact, observed behaviours indicate that they normally avoid contact
with each other.
The three different populations have been given
the following names by Orca researchers:
Offshore |
Resident |
Transient |
There is evidence of genetic differences between the
resident, transient, and offshore populations is that there are
subtle differences in the shape of their dorsal fins. These differences
are most consistently seen in females. One such consistent difference
is the shape of the fin tip. Resident dorsal fins tend to have a
rounded tip that terminates in a sharp corner. The dorsal fins of
off shores tend to have tips that are continuously rounded. Transient
dorsal fins tend to be more pointed at the tip, more closely resembling
the dorsal fin of a shark. The examples above are a bit exaggerated,
but illustrate the described differences.
The resident population is comprised of groups
of genetically related clans or extended family groups of Orcas.
These clans have established territories and fairly predictable
patterns of movement within those territories. They travel in pods
and sub-pods, often groups of up to 20 whales or more with individuals
scattered over a wide area.
Transients, on the other hand, have neither established
territories nor predictable patterns of movement. They swim in small
groups of two to five or six, usually in close physical proximity.
Researchers have recently had several encounters
with the third known West Coast Orca population, currently labeled
the "offshore". These whales have been encountered primarily
in the open ocean, and in large groups of 30 to 60.
One of the primary reasons residents, transients,
and off shores exhibit different behaviours is that their diets are
very different. Residents feed almost exclusively on fish, and exhibit
a strong preference for salmon. At the moment it is believed that
the off shores are exclusively fish eaters as well, but, given the
relatively small number of encounters with the off shores, it can't
be said with certainty.
Transient whales feed primarily on marine
mammals. Transients, observed in waters of B.C. and Washington State,
have been seen preying on seals, sea lions, dolphins, porpoises,
and other species of whales. Their diet, however, isn't strictly
limited to marine mammals. Transient killer whales have also been
observed eating sea birds, and the stomach of a dead transient whale
recovered up in Alaska contained the remains of a moose. Apparently
the moose chose the wrong moment to swim from one Alaskan island
to another--something that moose, deer and other land animals frequently
do.
Gray Whales also known as: California Gray Whale, Devilfish,
Mussel-Digger, Scrag Whale-Baleen Whale have no teeth.
Baleen is
long thick bristles
that filter food from silt on the ocean's floor.
Unlike most baleen whales, the gray whale must
get its food from the sediment on the ocean floor. The amphipods
the whales eat can be found there.
The favorite food of gray whales are amphipods. Amphipods are tiny shrimp
like animals that live in sediment on the ocean floor.
The whale's mouth will fill up with sediment.
The amphipods living in the sediment will also enter the mouth.
The whale will stay down for 3 to 5 minutes to eat. A trail of dents
in the ocean floor is left behind where the whale hit the ground.
The whale has no teeth to chew its food, so must
swallow it whole. Instead of teeth, the whale has baleen. The baleen
is made up of long fibers much like a broom. The baleen acts as
a filter. When the whales mouth is full, it closes forcing the water
out. The small animals the whale eats get caught in the baleen.
When all the unwanted material has left the mouth, the whale swallows.
The whale must surface to breath. It can
only stay underwater for 15 minutes before running out of air. When
it reaches the surface it will blow out a breath, creating a spout.
Many whales migrate south for the winter, especially
those that feed in northern waters. For the gray whale, the journey
begins in the frigid waters of the Chukchi and Bering Seas. The
whale spends the summer and a few fall months in the arctic waters
before heading south.
Around mid to late fall, the whales start their
5000-mile journey south to Baja California. Since whales travel
close to the coast, many people enjoy going out on boats to view
them. The gray whales are heading south for two reasons: shelter
and breeding.
Spouting
(Click here for audio)
Spouting is the visible exhaling
by the whale of air, water vapor, and water drops. Sometimes called
a blow.
Breaching
Breaching is when the whale leaps
almost clear of the water and falls back with
a splash.
Sounding
Sounding - When a whale sounds it
will show its flukes. The flukes are the whale's tail.
Spy hopping
Spy hopping is the whale pushing itself
vertically upward out of the water until it can see. A spy hop can
last from 15 to 30 seconds.
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