All whales belong to the order Cetacea, which comes from
the Greek word Cetus, meaning whales. They are also classified as
mammals, which means they nurse their young, have a four-chambered
heart, seven cervical vertebrae, and they have hair, which constitutes
only a few whiskers on whales. Because whales lack hair, which is
used to help to keep mammals warm, they have evolved blubber. Blubber
is just a thick layer of fat which helps to keep them insulated
in the often cold ocean water. In the bowhead whale this blubber
layer can be up to 20 inches thick because it lives in near freezing
water. A dolphin of the other hand may only have a quarter inch
of blubber because it lives in warmer water.
Like other mammals whales also give birth to live young and once
they are born nursing begins. These babies, or calves, are not born
with very much blubber so the milk that mothers feed their young
is high in fat, about 40 percent. Whales also have lungs like other
mammals and humans so they must come up to the surface to breathe.
To help them inhale and exhale while at the surface they have a
blowhole on top of their head, which acts like our nostrils. Whales
look more like fish than other land mammals because they live in
the water so they have adapted to live in that environment. Whales
have a streamlined body like a torpedo or a submarine to help it
swim faster. They have almost all the same bones that other mammals
do, but the bones have been modified for other purposes. The front
legs or arm bones have been modified into flippers for example.
Most whales have lost all but small hind legs bone which are similar
to bones found in terrestrial mammals.
The cetaceans can be further broken down into three suborders:
archaeoceti, or ancient whales or extinct whales; odontoceti, or
toothed whales; and mysticeti, or mustached or baleen whales. In
odontocetes all species have teeth, which is why they are called
toothed whales. They feed primarily on schooling fish and squid.
They also have a single blowhole, asymmetrical skulls, and they
Echolocating is when they send out high frequency sounds, and then
use the sound waves that bounce back from an object to distinguish
what the object is. Odontocetes include dolphins, porpoises, narwhals,
orcas, beluga, and sperm whales, among others. Mysticetes, or as
they are commonly called, baleen whales, use baleen to filter tiny
animals, such as krill, out of the water. Baleen whales have a two-hole
blowhole, and a symmetrical skull. Baleen whales are assumed not
to use echolocation because they lack the melon. The baleen that
they use to feed is made of keratin, like in human hair and nails.
The Whales filter out thousands of tiny animals (plankton) at once
using their baleen. They open their mouths and take in a mouth full
of water. Then they partially close their mouth, push the water
out over the baleen plates, and licking off the prey from the baleen
with their tongues.
There are three type of baleen whales, and they are defined by
their feeding techniques. Skimmers, like right whales and bowhead
whales, swim along with their mouths open and their baleen plates
exposed to capture prey. They catch mostly small, surface-dwelling
plankton, that cannot escape the slow-moving whales. Gulpers, or
rorqual whales, like humpback and blue whales, have throat grooves
that allow them to take big gulps of water, which they force back
through the baleen trapping their prey inside. The gray whale is
a gunker, the only one of its kind. It swims along the bottom on
its side and vacuums up mud and water. It then filters the sediment
through its baleen, to strain out the crustaceans from the mud.
These whales leave huge craters behind where they have been feeding.