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GLOSSARY
A
adaptation - Physical and behavioral changes that occur slowly over
time and help an organism to live more easily in its environment.
anatomy - The science of the structure of the body.
Andrewsarchus - A huge wolflike animal that lived from 42
to 40 million years ago. It was the largest carnivorous land mammal
that ever lived, and is thought to be a distant relative of the
whales.
B
baleen - Large plates that hang down from the upper jaw of some
whales. It is made of keratin, the same substance as your fingernails,
and used for filter feeding. In a fetus, baleen plates begin as
thickenings of skin on the upper jaw. At birth, baleen is soft and
short, but soon stiffens.
Basilosaurus - One of the early whales from about 40 million
years ago, thought to be an intermediate form between land mammals
and the modern whales. It had small but functional hind limbs, its
nostrils were situated on the top of the snout, and its ears had
adapted only partially to the marine environment.
bends - Slang term for decompression sickness (see below).
binomial nomenclature - A system of naming organisms, developed
by Linnaeus, using two latinized words, the first one indicating
the genus and the second the species.
blow - The expired air from a whale's blowhole that forms mist;
also referred to as the spout.
blowhole - The nostril of a whale. As whales evolved from land
mammals to marine mammals, their nostrils migrated up the forehead
to the top of the head. Baleen whales have two blowholes and toothed
whales have only one.
blubber - The layer of fat and oil below the skin. It provides
insulation for a whale, and is also important for buoyancy and as
an energy reserve.
breaching - The behaviour of a whale leaping almost clear of the
water and then falling back, creating a large splash.
bull - A mature male whale.
C
calf - A baby or juvenile whale that is still dependent on its mother
for protection and nourishment.
callosities - Light-coloured wartlike growths found on Right Whales.
They are generally located on the head and around the eyes and jaw.
calving - Giving birth to calves.
cetacean - A mammal in the order Cetacea that includes all whales,
dolphins and porpoises. From the Latin cetus (or Greek ketos),
meaning whale.
class - A scientific term used for organisms that share general
characteristics. All mammals are in the class Mammalia.
conduction - The transmission of heat through a substance from
a region of higher temperature to a region of lower temperature.
convection - The transfer of heat in a gas or liquid medium by
upward movement of the heated and less dense medium.
copepod - A small aquatic crustacean, eaten by whales; make up
a large portion of marine plankton.
COSEWIC - The Committee on the Status of Endangered Wildlife in
Canada.
cow - A mature female whale.
D
decompression sickness - A condition that results from nitrogen
bubbles in the tissues caused by rapid decompression (i.e., ascending
too quickly from depth while SCUBA diving). It can cause pain in
the joints, nausea, paralysis, etc.; also known as the bends.
dolphin - A cetacean with cone-shaped teeth, a beaklike snout and
a big brain.
dorsal fin - Fin located on the back of most whales that helps
them to swim straight.
E
echolocation - The use of reflected sound to locate objects.
euphausiids - Small shrimplike organisms that baleen whales feed
on.
evolution - A process over a long period of time by which organisms
change in response to their environment.
F
flippers - Pectoral fins, used primarily for steering, turning and
controlling the whale's vertical position in the water.
flukes - The lobes of a whale's tail. They consist of flat pads
of tough, fibrous connective tissue, completely without bones or
muscle. A whale's flukes are oriented horizontally, whereas the
tail of a fish is oriented vertically.
G
gulping - A method of feeding by baleen whales. The whale gulps
a huge amount of water containing plankton or small fish into its
pleated throat, raises its tongue and forces the water out through
its baleen plates; the food is caught in the plates and the whale
licks the baleen clean.
H
habitat - The surroundings in which an organism lives.
K
krill - The common name for euphausiid shrimp, which are small crustaceans
that many species of baleen whales feed on.
M
mammal - A warm-blooded animal with a backbone and hair that nurses
its young with milk from mammary glands.
melon - A fat deposit in the forehead of many whales that is used
in echolocation to shape and focus sound waves.
migration - Movement from one region to another with the seasons.
mysticeti - A suborder that includes all baleen whales. From the
Greek mystax, meaning mustache, which refers to the hairy
appearance of the baleen, and ketos, meaning whale.
N
notochord - A skeletal rod that supports the body of all vertebrates.
O
odontoceti - A suborder that includes all toothed whales. From the
Greek odontos, meaning tooth, and ketos, meaning whale.
P
physiology - The science of the functions of living organisms and
their parts.
plankton - Microscopic organisms that live just below the surface
of the ocean and drift freely or swim passively.
pod - A group of whales that travel together.
porpoise - A small cetacean with spadelike teeth and no beak.
R
radiation - The emission of energy as electromagnetic waves or moving
particles.
rorqual - A type of baleen whale that has many pleats (folds) in
its throat. Blue, Fin, Sei, Minke and Humpback whales are rorquals.
rostrum - The snout or beak of an animal.
S
skimming - A method of feeding by baleen whales. The whale swims
close to the surface with its mouth open and uses its baleen to
sift plankton from the water that enters its mouth.
sonar - A system developed by scientists in order to visualize
objects under water by sending out sound waves and listening to
their echoes. Sonar is an acronym for sound navigation
ranging. A whale uses a form of sonar called echolocation
(see above).
species - A group of organisms that can interbreed and produce
fertile offspring.
spout - The exhaled air of a whale that forms mist, often called
the blow.
spyhopping - When a whale pushes itself out of the water vertically
so that it can see above the surface.
stranding - Running aground or getting stuck in water too shallow
to swim away.
streamlined - Smoothly shaped to allow for easy passage through
air or water.
squid - A fast-swimming cephalopod mollusc with eight arms and
two long tentacles.
T
thermoregulation - The process through which organisms regulate
their temperature.
U
ungulate - A hoofed mammal.
V
ventral grooves - Throat grooves in rorquals and Grey Whales that
extend from the throat to the flipper area or farther. These folds
of skin and blubber expand the capacity of the mouth during feeding.
Because the excess skin folds into grooves, the whale maintains
its streamlined shape.
vertebrates - Any animal that possesses a spinal column, including
mammals, birds, reptiles, amphibians and fish.
vibrissae - Small, whiskerlike hairs found on some whales.
W
warm-blooded - Able to maintain a constant body temperature independent
of the temperature of the surrounding environment.
whale - A member of the order Cetacea, including whales, dolphins
and porpoises.
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