Five Things to Know About Iguanas

by AMNH on

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Today is National Iguana Awareness Day, so take the time to appreciate a few amazing things about these large lizards.


Slow and Steady

Iguanas aren’t very active animals. Most of the time these tree-dwellers don’t move much, blending into the forest canopy to avoid being noticed by predators. When they do move, they appear sluggish, but they’re capable of picking up the pace if pursued.


Iguana rests in a grassy area with a few dried leaves in the foreground.
Taking a leisurely stroll through a grassy area.
Courtesy of Ed Ivanushkin/Flickr


Triple Threat

Iguanas have a so-called “third eye” on the top of their heads. Known as the parietal eye, it looks like a pale scale and can’t discern shapes or color—but does sense light and movement, helping iguanas anticipate predatory birds from above. Thanks to their regular eyes, iguanas also have outstanding vision and can see color and movement at large distances.


VIew of an iguana's spiny head and neck and clawed front leg as it rests on a rock.
This iguana is a resident of the Virgin Islands.
Courtesy of Jeffy Can/Flickr 


Don’t Call Them Cold-Blooded

Their blood’s not cold, but iguanas depend on their environment to maintain their body temperature. Several anatomical features help them regulate their body heat, including their distinctive dewlaps, the large flaps of skin under their chin. At lower body temperatures, the lizards’ skin is darker to absorb more sunlight. As the iguana warms up, their skin grows paler to better reflect the rays.


Iguana with eyes closed rests on a horizontally-positioned plant stalk.
Napping on a plant stalk.
Courtesy of OlsenWeb/Flickr

Group Nesting

Female iguanas can lay dozens of eggs over the course of three days, into burrows up to 3 feet deep. When nesting sites are few and far between, females will band together to share.


Iguana pokes its head out of a hole that has been dug into the pebbly dirt.
Female iguana peeks out of her burrow.
Courtesy of Sally Taylor/Flickr


Flight or Fight

Iguanas are great swimmers and will try to escape a predator by diving into a body of water, then using its tail to propel itself away. If flight’s not an option, an iguana will threaten with its dewlap and bob its head aggressively, whipping its long tail, which is studded with spines. Like some other lizards, if caught by the tail an iguana can “drop” it to make its getaway, then regrow it at a later time.