Lizards are reptiles
of the order Squamata, which they share with the snakes. They
are usually four-legged, with external ear openings and movable
eyelids. Species range in adult length from a few centimeters
(some Caribbean geckos) to nearly three meters (Komodo dragons).
Some lizard species called "glass snakes" or "glass
lizards" have no functional legs, though there are some vestigial
skeletal leg structures. They are distinguished from true snakes
by the presence of eyelids and ears. Many lizards can change color
in response to their environments or in times of stress. The most
familiar example is the chameleon, but more subtle color changes
occur in other lizard species as well (most notably the anole,
also known as the "house chameleon" or "chamele").
feed on insects or rodents. A few species are omniverous or herbiverous,
such as the iguana. Iguanas are unable to properly digest animal
protein. Only two lizard species are venomous: the Mexican beaded
lizard and the Gila monster, both of which live in northern Mexico
and the southwest United States. They are typically not hazardous
to humans as their poison is introduced slowly by chewing, rather
than injected as with most poisonous snakes. Other small lizards
are harmless to humans (most species native to North America,
for example, are incapable of drawing blood with their bites).
Most lizards lay eggs, though a few species are capable of live
birth. Many are also capable of regeneration of lost limbs, such
as tails. Lizards in the Scincomorpha family, which include skinks
(such as the blue-tailed skink), often have shiny, iridescent
scales that appear moist. But like all other lizards, they are
dry-skinned, generally preferring to avoid water (though all lizards
are able to swim if needed).
Above Images Are From The US Fish & Wildlife Service