Page 59 - Reptiles & Dinosaurs (Britannica Illustrated Science Library)

54 LIZARDS AND CROCODILES REPTILES AND DINOSAURS 55

Changing Colors

hameleons are well known for their ability to change color. PANTHER Feeding Habits
Another interesting fact is that their tongue can stretch great CHAMELEON These diurnal hunters wait for victims to
Furcifer pardalis
C distances in seconds. They live mostly in Africa. Their pass by. Their diet includes arthropods and
small invertebrates. Among insects, they
prehensile tails and toes make them excellent climbers. Another helpful Range Madagascar prefer crickets, grubs, cockroaches, and
characteristic is that their eyes can move independently of one another, PREHENSILE TAIL Habitat Coastal Regions moths. Other species on the menu also
include songbirds and mice.
providing them a 360° field of vision. Their flat bodies help them to balance They use their long Lifestyle Diurnal
and to hide among the leaves. curved tails to hold on
to branches without
using their feet.

14-20 inches (35-50 cm)

BONE
acts as a support for
discharging the tongue.

TIP
The tip of the
tongue spreads
TONGUE out and captures
Covered with the prey with its
collagen tissue. sticky surface.

Protractible Tongue 1 Contraction 2 Unfolding 3 Retraction
Long and lightweight, the chameleon's tongue is Several sheets of collagen The accelerating When the elastic
sticky and can be extended. Chameleons throw their between the tongue and muscle compresses tissues contract again,
tongues outward like projectiles to hunt their prey. the accelerating muscle the energy-storing they roll up the tongue
are compressed in the collagen tissues, and return it to its
form of a spiral, which launching the tongue initial position with the
stores the energy toward its target. prey sticking to it.
necessary to propel the
tongue outward.

Up to 600%

of the tongue's length is
curled up in reserve.

FEET
The toes are divided
into two parts, with two
How It Changes Color Reflected Incident Reflected Incident toes on the outside and
Light
Light
Light
Light
three on the inside.
The color-changing ability of chameleons, well known in popular When the PIGMENT The melanophores
sayings and songs, is not an adaptation to the environment as is A upper layer CELLS B contain a dark pigment 2 Toes
widely believed. Rather it is related to changes in light and (chromatophores) called melanin, which
temperature, courtship behaviors, or the presence of a predator. detects a yellow color, Chromatophores regulates the
Color changes are caused by the action of hormones on pigment the blue light of the brightness and the
cells in the skin. These specialized cells, located in each layer of the guanophores (white Guanophores amount of light 3 Toes
dermis, react and change color, camouflaging the chameleon from chromatophores) reflected, varying its
its predators. becomes greenish. Melanophores color.