Page 8 - Amphibian

What is an amphibian?

Living amphibians are divided into three groups – frogs
and toads; newts, salamanders, and sirens; and the little-
known, wormlike caecilians. Amphibians are vertebrates
(animals that have a backbone) like fish,
reptiles, birds, and mammals. They

IN AND OUT OF WATER are cold-blooded, which means that their body
This amphibious car can temperature varies with their surroundings.
be driven on land or in
water. The words Unlike warm-blooded animals (mammals and
“amphibious” and birds), amphibians do not need to eat frequently
“amphibian” come from Skin
the Greek amphi and bios to maintain their body temperature, so their food of panther
meaning “double life,” intake increases or decreases with their toad (above)
that is, they can live or
function on land and in temperature and activity level. Amphibians have
water. Most amphibians
pass from a free-living, a naked skin (lacking hair, feathers, or surface
aquatic (in water), larval scales) and can breathe through their skin as
stage into a terrestrial, or
land-based, adult. well as, or instead of, through their lungs.
Skin of tree
frog (right)
ONLY SKIN DEEP
An amphibian’s skin is very special. Like all
amphibians, frogs and toads use their skin
to breathe through, lose or take up water,
produce color patterns and markings
for defense (pp. 20–21), and to
attract a mate (pp. 32–33). They
also secrete mucus from their
skin to keep it moist
and to protect it from
being damaged.

A European common frog
lives in woodlands close to
water and ranges in length
from 2.5–4 in (6–10 cm)

FROG-SHAPED Smooth, slimy Fire salamander’s
Frogs and toads (pp. 42–45) have a skin of frog markings display
distinctive body shape – a large is typical polymorphism
head with a wide mouth, prominent
eyes, usually a fat body, no tail, back
legs longer than the front ones, and
an “extra” (third) heel section to
the leg above the long foot. They
probably evolved these features
to chase, jump after, or lunge at
insects on the move (pp. 18–19).