November 2002
SeaWorld/Busch Gardens
Killer Whales
Background Information
Killer whales are dolphins.
Killer whales are members of a scientific family of toothed whales called the Delphinidae.
The Delphinidae is also called the dolphin family. The killer whale is the largest member
of the dolphin family.
Where in the world?
Killer whales inhabit all the oceans of the
world. They're most numerous in the Arctic,
the Antarctic, and areas of cold water
upwelling, where the nutrient-rich water is
thick with fishes, seals, sea lions, and other
marine mammals that are prey for killer
whales. Although the worldwide population of
killer whales is unknown, they are not endan-
gered.
Killer whales are mammals—like you.
Killer whales are marine mammals. They're
warm-blooded, breathe air, give birth to live
young, and nurse their offspring. They breathe
through nostrils located on top of their heads,
called a blowhole. Maintaining a constant body
temperature is a challenge for mammals that
live in the sea, where body heat is lost 27 times
faster than in air. Whales and most other
marine mammals have a thick layer of fat
called blubber under their skin. This fatty
padding insulates the animal and helps it main-
tain a constant body temperature.
Killer whales are mammals like us.
They're shaped for swimming.
A sleek, streamlined body helps a killer
whale move through the water efficiently. They are among the fastest-swimming marine
mammals, able to reach top-speeds of up to about 48 kph (30 mph). Usually, though, they
cruise at much slower speeds, between about 3 and
Killer Whales • Background Information • page 1
7 kph (2-4 mph). Strong muscles along the whale's back move the tail flukes up and down,
providing power for swimming.
Flippers and fins.
A killer whale uses its rounded, paddlelike pectoral flippers to steer and, with the help of
the flukes, to stop. The pectoral flippers contain the major bones found in the forelimbs of
land animals, but they are modified and shortened.
The dorsal fin on a killer whale's back contains no bone. It's made of dense, fibrous
connective tissue. A male killer whale's dorsal fin is tall and triangular. It may reach a
height of 1.8 m (6 ft.). In females, the fin is smaller, only 0.9 to 1.2 m (3-4 ft.) and may
curve slightly backward. Some whales have irregular shaped dorsal fins, which may lean
to the left or the right.
Eyespots and saddles.
Killer whales are easily recognized by their striking coloration. White and gray markings
create a sharp contrast on the whale's black body. A white "eyespot" is located just above
and slightly behind each eye. Just behind the dorsal fin is a gray saddle. The whale's belly,
lower jaw, and underside of its tail flukes are white. This coloration is a type of disruptive
coloration, a form of camouflage in which the color pattern of an animal breaks up its
body shape. By the flickering, filtered sunlight of the sea, other animals may not recognize
a killer whale as a potential predator.
Sound in the sea.
Killer whales have excellent hearing. Studies show that killer whales can hear frequencies
from about 0.5 to 100 kHz.
By comparison, the average hearing range for humans is about 0.02 to 17 kHz. Killer
whales probably rely on sound to hunt, navigate, and communicate in murky waters. They
produce clicks and
sounds that resemble
moans, trills, grunts,
squeaks, and creaking
doors, as well as “whis-
tles.”
Big, bigger, biggest.
Baby killer whales,
called calves, are about
2.4 m (8 ft.) long and
weigh about 135-180 kg
(300-400 lb.). They're
born in the water and
nurse for about one
year. Female killer
whales are called cows. Killer whales have a white eyespot above and slightly
behind each eye.
Cows average about 5 to
Killer Whales • Background Information • page 2
7 m (16-23 ft.) and about 1,360 to 3,630 kg (3,000-8,000 lb.). Male killer whales, called
bulls, are usually larger than females. A mature bull averages about 7 to 8 m (23-26 ft.)
and usually weighs between about 3,600 and 5,400 kg (8,000-12,000 lb.).
Pods and pecking orders.
Killer whales live in groups called pods. A pod may have less than 5 to about 30 individuals:
a mix of males, females, and calves of varying ages. Sometimes, several smaller pods join
together to form larger herds of 50 or more whales. A social hierarchy, or "pecking order"
exists within each pod. The most dominant pod member is a mature female. The whales
establish dominance and rank themselves by slapping their tails against the water, butting
heads, jaw-snapping, and other gestures. Researchers have been studying the
population dynamics of killer whale pods. They can identify individuals by taking pictures
of the whales' dorsal fins, noting differences in shape, relative size, scars, and deformities.
The saddle area just behind the dorsal fin is another identifying characteristic.
Top predators.
Killer whales are the top predators in the ocean. Their diet varies from one region to
another, but may contain fishes, squids, seals, sea lions, seabirds, other whales, and occa-
sionally penguins and sea otters. Killer whales have often been compared to a pride of
lions or a pack of wolves because, like these animals, the pod hunts cooperatively. They
work together to encircle and herd prey into a small area before attacking. Sometimes
these powerful predators slide out on sand bars or ice floes to pursue prey. They have even
been known to surface under ice floes to throw their prey into the water.
Resident killer whales living off the coastlines of British Columbia and Alaska
feed on fish and squid.
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