Killer Whales (1605 words)

Killer Whales
Whales are giant creatures that live in the sea. They look like fish, but are
not. Whales belong to the group of animals called mammals. Whales belong to the
group of mammals called cetaceans, which comes from a Latin word meaning large
sea animal. There are two major groups of whales. The first group is mysticeti
(baleen whales), and the other isodontoceti (toothed whales). In the group
odontoceti, there is a family of whales called delphinidae (dolphins and small
toothed whales). In this report, I will focus on a species of whale that comes
from this family, and that species is the killer whale, or also known as orcinus
orca, or just orca. The largest and most striking of the dolphin family, the
killer whale is one of the most fearsome predators of the deep. Killer whales
are basically the same shape as fish, but they differ in many ways. One of the
most obvious differences is the tail fin. Fish have vertical tail fins, while
whales have horizontal tail fins. One of the most distinctive features of orcas
is the tall, wide dorsal fin located on its back. In females, the dorsal fin can
grow to about 2 feet high. It is falcate (hooked or curved). In males, the
dorsal fin is triangular in shape and can grow up to about 6 feet high. Another
distinctive feature of killer whales is that they possess a sleek, black and
white pigmentation pattern. A white patch is located above and behind the eye.

An extensive white ventral patch extends onto the flanks (sides). “There is a
gray saddle behind the dorsal fin, which is black at birth.” (Hoyt, Pg. 32) At
birth, orcas are about 2.1 to 2.4 meters long and weigh about 180 kilograms.

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When they are adults, males grow to about 9.5 meters long weighing 8 tons or
more. Females grow to 8.2 meters long and weigh 4-6 tons. “Orcas have robust
and graceful bodies with a conical or rounded head.” (Hoyt, Pg. 97) It has no
distinct beak. They have straight mouthlines. Another physical attribute of
killer whales, besides having a tall dorsal fin, is that killer whales have
large, paddle-shaped flippers. These flippers are 2-3 times larger in males than
they are in females. Killer whales are very large physical specimens. Being
known as a fearsome hunter with killer instinct, it would be interesting to know
what a killer whale’s diet consists of. The orca resembles the great white
shark in its predatory skill and range of food. They eat seabirds, turtles,
fishes, including sharks, whales, dolphins, porpoises, seals, and sea lions.

These hunters feed in groups of two to twenty animals. They can even kill baleen
whales much larger then themselves. They have 10 to 13 teeth on each side of
each jaw, which helps in their feeding. Though killer whales sometimes attack
dolphins, seals, and other whales larger than themselves, but they have not been
known to attack people, although there have been documented cases of killer
whale attacks. Throughout the ages, whales have lost some of the characteristics
of mammals. Mammals have hair covering their bodies. Whales have only a few
stiff hairs on their heads. Mammals have four legs. A whale has no hind legs.

The only traces that they remain are two tiny hipbones. The front legs have
developed into flippers, which are used for steering or keeping its balance.

Although killer whales share the same characteristics as mammals, they also have
special features that allow them to live in the water. Whales have many special
characteristics suited for living in the water. Living in water enables them to
reach enormous sizes. “The buoyancy (lift) of water helps support a whale’s
body, which makes it possible for them to grow larger.” (Ellis ; Knoph,
Pg.18) Orcas have a highly streamlined shape. This enables them to swim with a
minimum of resistance. The powerful tail fins called flukes are horizontal.

Whales swim by moving the flukes up and down. Another characteristic that is
helpful to killer whales, or any type of whale, is that a whale’s backbone,
ribcage, and shoulder blades resemble those of other mammals. Almost all mammals
have seven neck vertebrae. In killer whales, these vertebrae are compressed into
a short length or joined together into one bone. This keeps the head from moving
about. It also joins the head directly to the body. Orcas have smooth, rubbery
skin that easily slips through the water. Mammals have hair to keep them warm.

Whales have only a few hairs on the head. To keep warm, they have a layer of fat
called blubber. The blubber grows to about 6 inches thick never growing more. If
there is no food around or there is little food, killer whales can live off
their blubber for a long time. Since blubber is lighter than water, this
increases the buoyancy of whales. Much like their mammal brethren, whales have
lungs and must come to the surface to breathe. They can hold their breath for
long periods of time. Their muscles store more oxygen than the muscles of other
mammals. Orcas store 41 percent of their oxygen supply in the muscles. When
diving, the body reduces the blood flow to the muscles, still keeping a normal
flow to the heart and brain. The heartbeat slows helping to save oxygen. After a
dive, a killer whale must take several breaths to recharge its tissues with
oxygen before diving again. When an orca comes up to breathe, it rolls forward
as it breaks the surface. This movement gives it only about two seconds to blow
out and breathe in up to 2,100 quarts of air. They breathe through nostrils
called blowholes. These are located at the top of the head. Orcas have one
blowhole. Powerful muscles and valves open the blowhole wide so the whales can
breathe. Then they snap tightly shut. A cloud called a blow or spout is produced
when a whale exhales. It consists of water vapor. Sometimes it may include mucus
and oil droplets. An interesting aspect of whales is that they utilize most of
the five senses that humans use. The five senses are hearing, seeing, smelling,
touching, and talking. Killer whales have no sense of smell and have poor
eyesight. They have well-developed senses of touch and hearing. “Their keen
hearing provides them with information about their surroundings.”
(International Experts, Encyclopedia survey, 1988) They can hear a wide range of
sounds, including low-and high-pitched sounds that are beyond the range of human
hearing. They can also tell from what direction a sound is coming from. Killer
whales produce sounds within the nasal sac system, a series of air-filled
pouches around the blowhole. They locate underwater objects by listening for
echoes produced when the objects reflect the sounds. They determine the distance
and the direction of an object through the echoes. This is called echolocation.

When researching any type of animal, it is also worth knowing the life span of
the animal being researched. Knowing the life span of killer whales is useful
information that a researcher can later use. Knowing the life span of the killer
whale helps the researcher understand how the killer whale lives and how long it
lives. The life span of killer whales is 50+ years for the males and 80+ years
for the females. Human hunters account for many of the deaths. Except for
people, whales have no natural enemies. Most of the whales that escape the
hunter’s harpoon live to old age and die of natural causes. Some orcas die after
stranding themselves on a beach. In some cases, a whale swims ashore alone. In
other cases, an entire pod of whales becomes stranded. People often return
beached whales to the sea, but most swim back onto the beach. They cannot live
long out of the water. They may overheat, become crushed by their own weight, or
drown when the tide covers their blowholes. Another important aspect worth
noting is how killer whales reproduce. The way that killer whales reproduce is
very unusual as compared to other mammals or even other whales. Killer whales
mate during a specific season. The male, called a bull, and the female, called a
cow, engage in playful courting as part of the mating process. The whales stroke
each other with their flippers during courting. Females breed at 9 to 10 years
while males breed at 16 to 17 years. The gestation period or pregnancy period
lasts 13 to 17 months. A female will give birth every 10 years, sometimes every
3 years. A whale has only one baby at a time. A baby whale is called a calf.

Twins rarely occur. During birth one or more females may help the mother. Whales
are already giant animals at birth. Calves are born in fall and winter. They are
8 feet long and grow 4 inches every month. As soon as the baby is born, the
mother nudges it to the surface to take its first breath. She stays close to it
for at least a year. During this year, the female will nurse her calf. She has
special breast muscles that pump milk into the baby’s mouth. “Whale milk is
highly concentrated and rich in fat, protein, and minerals.” (Leatherwood
& Reeves, Pg. 134) This helps the calves grow amazingly fast. Overall, there
are a plethora of characteristics and attributes that make killer whales unique.

Whether it is the killer instinct, life span, or method of reproduction, it is
easy to see that killer whales are very special creatures. Though there are many
different kinds of whales, I chose to write about one specific species of whale:
the killer whale or orcinus orca. Whales are thought to be along the lines of
gentle of nonviolent. Killer whales, however, are neither. It is these
characteristics of the killer whale that many people find intriguing. Whales, in
general, are very unique creatures. The killer whale is unique in its own way,
and possesses certain characteristics that most whales do not. It is the killer
instinct found in killer whales that makes them intriguing and distinguishes
them from other species of whale.


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