Appearance Of
Common Green Iguanas

The green (or common) iguana (Iguana iguana) is an arboreal (tree living) and diurnal (daylight active) lizard usually found at elevations below 3,000 feet in tropical and subtropical regions from northern Mexico to central South America.  It is most often found in the vicinity of rivers and streams.
    Iguanas have short, powerful limbs equipped with strong, sharp claws (for climbing and digging), and a long, strong tail.  They can reach lengths of 6 to 6-1/2 feet.  A large flap of skin (the dewlap) hangs from the throat and helps regulate body temperatures.  Iguanas also have a prominent crest of soft spines (longer in the males) along the midline of the neck and back, beginning at the base of the skull.
    Male iguanas tend to be larger and have brighter overall coloration than females.  The distinct color of males is especially pronounced during the breeding season.  Males tend to have larger heads than females, in part because of swollen jowls.  Both sexes have 12-13 prominent pores arranged in a row on the underside of both thighs.  These glandular structures secrete a waxy substance with which iguanas  mark their territory and identify each other.  As the males mature, their "femoral pores" develop slight outward projections.  This developmental modification probably enables the male to better grasp the female during copulation.
    An iguana's skin is entirely covered with very tiny scales.  Iguanas cannot change their coloring (as chameleons do), but certain areas of their skin can become darker when exposed to direct sunlight.  Young iguanas are pale green with dark ringed tails.  They mature to a lighter, more earthy color, usually with dark vertical bars on the body and tail.
    Vision, hearing and the sense of smell are acute.  In their  natural environment, iguanas tend to be very wary, hiding or fleeing at any sign of danger.  Iguanas are somewhat clumsy but accomplished tree climbers.  They tend to bask by day on tree branched, often over water.  When frightened or threatened, they usually drop (sometimes from great heights) into the water below.  Being excellent swimmers, they quickly make their way to protective cover by pressing their front limbs along their sides and swishing their powerful tails from side to side.  Iguanas can also safely land on the ground and run to protective cover after jumping from substantial heights.  When threatened or cornered, iguanas can defend themselves with astonishingly quick, whip like lashed of their tails and with their claws and jaws.
    Iguanas mate in January or February.  After a pregnancy of about 2 months, the female digs in moist sand or soil, usually near the base of a tree, and deposits 25-40 eggs.  The hatchlings, measuring 25-30 centimeters long, emerge in about 2 weeks.  They grow 15-24 centimeters a year and attain sexual maturity in about 3 years.