ORCAS are marine mammals: they are warm blooded, air breathing, and bear
their young alive. There is only one species of orca (Orcinus orca).
However, geographical isolation may have created different unique races and
populations. Near the Washington, British Columbian and Alaskan coasts we
know that there are at least two distinct races of orcas. These are
referred to as Transients and Residents. Even though these two groups
share the same ocean space they differ in their social habits, range, diet
and to some extent even their physical appearance. In recent years a third
population, "Offshore", has been discovered living in waters adjacent to
the Pacific Northwest. Not as much is known about this group, as sightings
have been infrequent. They probably represent another orca community
rather than a unique race of orcas.
Orcas are the largest member of the dolphin family, Delphinidae. Males
grow to a maximum length of about 32ft (9.8m) and weigh 10 - 11 tons
(9-10,000kg). Females are smaller and grow to a maximum length of 28ft
(8.5m). They may weigh as much as 7-8 tons (6,500 - 7,500 kg). Calves at
birth are about 8ft (2.4m) long and weigh about 400lbs (180 kg).
Orca bodies have distinctive black and white markings. The upper body of
orca is mostly black except for a white-grey "saddle" patch located on
either side just behind the whale's tall dorsal fin. The underside is
largely white. Both females and males have similar markings except on the
underside, where it is possible to distinguish male from female. Orcas are
one of the toothed whales (Odontoceti), as are other dolphins and
porpoises, pilot whales and sperm whales etc. Orcas have 10 to 13 pairs of
interlocking conical teeth in the upper and lower jaws, usually a total of
48. Sperm whales have teeth only in the lower jaw. Orcas use their teeth
primarily for grabbing prey. The number of rings within the teeth (anuili)
may indicate how old an individual is.
Orca skin is relatively thin. It feels rubbery to touch but is very
sensitive. Orcas like to rub their bodies on each other and even scratch
each other by raking their teeth over different areas. This means their
bodies are often scored. In the Pacific Northwest, some orcas like to rub
their bodies in the shallows of special beaches which are covered in small
smooth stones. Underneath their skin they have a layer of blubber which
keeps them well insulated from the chill of the ocean.
Orcas are easily recognized by their distinctive dorsal(located on the
back) fin. The dorsal fin distinguishes male and female adults. In the
mature male the erect dorsal fin may reach a height of over 5 1/2 ft (1.8m)
but the female dorsal fin grows only to an average of 3ft. (0.9m). By
taking photographs of the dorsal fins of orcas, Dr. Michael Bigg and his
colleagues at the Pacific Biological Station in Nanaimo, B.C. were able to
identify each individual orca living in the Pacific Northwest. After
compiling thousands of photographs they were able to define the composition
of the orca population. Each individual was assigned a number and an
alphabetical letter which designated the individual's pod. The
alpha-numerical system, and yearly photographic updates, has enabled
researchers to keep track of pod members.
Each orca also has two large pectoral fins located on each side of the
body. These are probably used for balance. The bones inside these fins
are remarkably like those of a human hand, but the outer covering resembles
Like all whales orcas have a graceful tail. This is called their flukes.
The flukes help propel the whale through the water. Orcas are very strong
swimmers and can go very fast at times.
Orcas are found in all the oceans throughout the world. The most
persistent sightings have been near the continental shelves off Japan, the
North American Pacific Northwest, Iceland, Norway, Scotland and Antarctica.
However, nowhere are their populations very large.
In the summer and fall seasons (from June through November) of the Pacific
Northwest, resident type orcas take advantage of the adundance of salmon
runs, so a lot of foraging (feeding) behaviour is observed during this
time. Although resident orcas generally fish individually, they probably
co-ordinate their movements as a group to maximize their chances for
success. The group (whether it is a small maternal group, several maternal
groups or several pods) usually spread out over an area. Together they
will move in the same direction. Quick, brief, changes in direction
indicate that a whale has located a fish. These (resident) whales do eat
other fish such as herring and "bottom" fish, but their preference is for
the five different species of Pacific salmon. In other parts of the world,
such as Norway, orcas eat mostly herring and have been filmed
co-operatively hunting herring.... first forcing the herring into a tight
ball by startling them, then (using their flukes) some whales in the group
stun the fish while others take advantage and feed.
Squid has been found in the stomachs of Offshore orcas.
Transient orcas prefer to eat marine mammals and birds. They have never
been observed eating fish. The Transient population of the Pacific
Northwest has been identified as a distinct race. Their range encompasses
the same waters as the Resident Communities of Washington state, British
Columbia and Alaska. No one understands how these two races developed, but
most likely they have been genetically separated for over 100,000 years.
Perhaps the last ice age brought about geographical separation which
encouraged separate breeding, cultural and feeding traditions which have
remained constant since that time.
Physically, the two races are very similar, but there are a some visible
differences. The top of the dorsal fin of Transient orcas tends to be more
pointed than that of Resident orcas. Less obvious, the saddle patch is
located further forward on Transients.
Transients cruise the coastal waters in search for Harbour seals, sea
lions, Dall's porpoise, Harbour porpoise, Pacific Whitesided dolphins,
Gray, Minke and other whales. Their hunts are highly coordinated and
co-operative efforts. Sometimes a hunt will take just minutes, but at
other times they last for several hours. Much of the time, Transients
travel around silently in small groups. This perhaps enables them to
listen intently, lessen their presence in the water, and sneak up on their
prey who have well developed skills of their own and are difficult and
unwilling victims. It is even thought that Transients will modify the
sound of their own blows and echo location to confuse their prey.
Orca are very social animals. They live in small nuclear and extended
families that we call pods, clans and communities. At the social heart is
the orca mother. She and her children (the maternal group), even her adult
sons, stay together throughout life. Adult daughters who have their own
offspring may separate from their mother to some extent, in order to take
care of their children's need, but will usually be found travelling nearby.
Beyond the central mum groups, the pods are extended families of closely
related mothers that are daughters, sisters or cousins, and their children.
A pod can be defined as those orcas that are usually seen travelling
together. For Resident orcas of the Pacific Northwest a pod may number
from 5 to 50 individuals. Pod continuity extends across generations. As
individual lives are long, and changes to pod composition are slow,
development of new pods can take a long time, possibly many generations.
Because resident orcas are such social animals, it is not unusual to see
large numbers of maternal groups and pods come together and share the same
Clans are defined in term of the acoustic traditions of pods within an orca
community. Pods which share common calls belong to the same clan.
Separate clans are composed of pods which do not share calls. Pods from
separate clans commonly socialize with each other within the community,
even though they do not share any of the same calls.
In Washington and British Columbia the Resident orca pods form two distinct
Communities: Southern and Northern. These two communities total about 300
individuals. The Northern Resident Community has about 200 individuals
who belong to 16 pods, whereas the Southern Resident group has about 100
individuals who belong to three main pods. All these pods are comprised of
a collection of different maternal groups. The whole community is a
support system for each individual, everyone is there for each other.
Overt violence or aggressive behaviour between individuals, even among
males, has never been observed. Instead, orca society is marked by
co-operation, co-ordination, communication, trust and acceptance.
During the summer season, when orcas are observed the most, the whales
spend many hours intermingling with one another, with other maternal
groups, with pods from the same clan and with pods from different clans.
In the Northern Resident Community, preceding the arrival of a new group,
one of the more frequent user groups may leave the area in order to
"escort" the new group into the area. As they enter, the whales often
pause in their travel. Other orcas already in the area may then come
toward the arriving group, and together they may (often after an intense
vocal period) become quiet, rest on the surface and then begin to socialize
with each other by spyhopping (lifting their heads out of the water),
rubbing bodies together, breaching (where the whole whale jumps free of
the water), tail and pectoral slaps and deep diving. On occasion the
greeting whales may turn around before reaching the arriving group and
travel ahead. Usually, for the Northern Resident whales, once they have
entered the area they head for the "Rubbing Beaches". These beaches are a
unique feature of the area. Though whales have been observed rubbing in
other shallow areas, their use of these particular beaches is very
consistent and well documented. It seems to be an important aspect of
their traditions. The beaches are covered with small flat, round and
smooth stones. The whales dive, blow out air as bubbles, to lessen their
buoyancy, and then skim their bodies over the stones. Sometimes several
whales will use the beach at one time, but they will also take turns,
waiting a short distance offshore for their turn. This activity brings the
whales very close to shore. Sometimes their vocalizations are very weird
and wonderful when they are enjoying the beaches.
Orcas are primarily acoustic animals. This means that they gain most of
their knowledge about their environment and each other through their well
developed sense of hearing. Their eyes, located on each side of their
head, offer an orca about the same ability to see in the water as a cat
might have in the air. Orcas also have a kind of sonar, called echo
location, which enables them to find prey or navigate during night time.
Echo location signals are produced in cavities within the head and emitted
from the fatty "melon" located in the front part of the orca's head. When a
whale sends out an echo location signal, which sounds like a series of
clicks, the signal hits an object and bounces back (as an echo) to the
whale. The whale's sizable brain, which is nearly four times as big as a
human's, processes the information and the whale can then "see" the object.
Communication lies at the core of orca social awareness. Family members
are seldom out of hearing range of one another. Their calls, as loud as a
jet plane's engines, echo over many miles in the ocean. Everyone knows
where he or she is and where everyone else are too. Given the strength of
their attachments to each other, this must have a very calming effect on
them. Communication is an essential ingredient of the glue that brings
harmony to the orca community.
Orcas make three types of vocalizations: clicks, whistles and pulsed calls.
The clicks are part of the whale's sonar and are used for echolocation:
for finding and location food sources, for defining other objects in the
ocean and locating the whale in its environment. Whistles are typically
continuous tone emissions that may last for many seconds.
Calls, simply put, are pulsed signals which have discrete patterns that can
be recognized by ear or by spectrogram. They are the main component of the
orca communication repertoire. When Dr, John Ford categorized the discrete
call types for the orcas of the Pacific Northwest he discovered that each
pod has its own collection of calls which he called their "dialect". He
was then able to define larger acoustic groups or clans by grouping
together pods which share common calls. Only pods which share common calls
are part of that clan. The differences in vocal call types between clans
does not seem to limit the various maternal groups and pods within a
community from coming together and socializing.
The role of these calls is not known. The different calls are a way for
the whales to keep track of each other over large distances, in the dark,
or when large congregations occur. Though it has not been demonstrated,
there is certainly potential for communication of complex specific
information in calls. Sometime groups are very vocal, and at other times
the groups may be silent. The calls are not necessarily modified in sound
level to accommodate whales travelling close together.
On the surface, orca communities such as the Northern Resident Community,
seem to be surviving and thriving. Annually, this community increases by
about 2%. But there are concerns. We know that orca communities are very
localized and never very large. They are self contained, perhaps even self
sustained social units. They are therefore very fragile and need
In Japan, coastal whaling and live captures have removed over 1600 orcas
since the send of World War II. Most likely, if there were resident type
populations in Japanese waters, these are now destroyed. Sightings of orca
are now very rare. In February 1997 a group of 10 Transient type orcas
passed offshore of Taiji. This was the first such sighting in ten years
and the whales were immediately rounded up by being driven into shore.
Five members were shipped away to aquariums. Three of the whales were
young females, one who later died was pregnant. Survival prospects of the
Japanese orca population must be precarious at best.
The Pacific Northwest communities, especially the Southern Community, came
close in the 1960s and 1970s, to the same fate as the Japanese population.
Almost 70 orcas were removed from this population for the captive industry.
Many died in the capture attempts, and as young juveniles were preferred,
a whole generation disappeared. It has taken the Southern Resident orcas
almost thirty years to recover their former numbers.
When it was no longer popular to capture whales in the Pacific Northwest,
the captive industry shifted their efforts to Iceland. Since the 1970's
that population has been hit very hard, and many of its members, including
famous Keiko (Free Willy) were shipped away and lost to their families.
Unlike the the Pacific Northwest, there is not even any knowledge about the
Icelandic population, and so we may never know what damage has been done.
Many hundreds of Antarctic orcas have been hunted and killed by Russian and
Japanese whalers. Again, we will never know what damage to the population
this has done.
viewer discussion .
the debate .
inside seaworld .
other captive orcas .
ted griffin .
navy dolphins .
man & marine mammals .
press reaction .
tapes & transcripts
web site copyright 1995-2013 WGBH educational foundation