Page 57 - One Million Things: Animal Life - The Incredible Visual Guide
P. 57
BIRD INSECT
As active fliers, birds need much Holes called spiracles in
more oxygen than mammals, and an insect’s thorax and abdomen
have a more efficient respiratory allow air in and out of its body.
system. Nine air sacs work like Spiracles lead to branching tubes
bellows to maintain a one-way called tracheae that carry oxygen-rich
flow of air through the lungs, and air to all parts of the body, and
to clear any used air quickly. remove carbon dioxide.
Spiracle in
the side of
a grasshopper’s
abdomen
MAMMAL AQUATIC MAMMAL
Like other mammals, a hamster Whales and other marine mammals have
has two lungs. The lungs are made lungs and, unlike fish, cannot extract
up of millions of tiny air sacs, each oxygen from seawater. They must come
surrounded by blood capillaries that to the surface to breathe air, although they
carry oxygen away. Air is sucked into can wait much longer between breaths
or squeezed out of the lungs by than land mammals. A whale has a nostril
muscles that make the chest cavity or nostrils—called a blowhole—on top of
bigger or smaller. its head. When it surfaces, stale air (and
any water lodged in the blowhole) is
blown out as spray.
AMPHIBIAN ADULT
Once it reaches adulthood, an
amphibian, such as this frog, takes
in oxygen through its lungs. In order
to breathe, the mouth closes and air
is drawn through the nostrils and
into the lungs. Then the body wall
contracts (squeezes) to push air out
of the lungs. Frogs also take in
oxygen through their moist skin.
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