Page 29 - Amphibian

GETTING TO THE TOP Muscles in MAKING WAVES
Tree frogs (pp. 50–53) are well adapted tail growing When tadpoles first wriggle free of
for climbing, leaping, and walking on the Left stronger their egg mass (pp. 38–39), they
smoothest, shiniest leaf surfaces. This front and are barely able to swim at all. As
little White’s tree frog can even climb up a hind legs the tail muscles strengthen and the
near-vertical pane of glass, because on the closing up tail fin develops, the tadpole swims
ends of its fingers and toes, there are 1 by making a series of undulating,
special disks, or pads, or S-shaped, waves that pass down
containing sticky mucus. the tail from the base to the tip.
These pads help a frog stick Before the limbs develop (1), the
to a surface. Larger, heavier tail provides all the power
tree frogs have extra pads Tail fin needed to propel the
beneath the finger and toe tadpole forward (2). As
joints for more sticking power, Mucus covering the limbs develop, the
and their belly skin also helps disk helps frog tail is absorbed,
them to cling. cling to trees providing nourishment
for the developing
tadpole. The tadpoles
Lateral line have changed into froglets, and
With the next step, they are able to leave the pond.
right front and hind 2
legs come together
American bullfrogs stay in
the tadpole stage for two to
three years – these four are
about two years old, but so
far only two (3, 4) have
3 developed legs
S-shaped
swimming
motion

White’s tree frog 4
climbing up a
pane of glass
Hind leg developing
SPLASHDOWN!
The frog breaks the water’s
surface with a big splash and a
loud plop, which is distracting to
its enemies (pp. 58–59). It has
now reached a safe place and will
either dive deep into the pond or
hide among weed beds. The body
curves upward when the frog
enters the water, allowing it to
take a gulp of air before
swimming off. Body curving
upward upon
Webbing on foot entering water
provides some
of the frog’s
propulsion
in water

SUPERFROG!
This northern
leopard frog, leaping
free of the water’s
surface, shows just
how powerful the leg Front leg
muscles can be. Not coming down
only do they lift the into water acts
frog’s body weight, they Northern leopard as a brake
also have enough extra frog completing
power to overcome the its leap into water
water’s surface tension.

27 Continued on next page