Color-Changing Chameleons Struggle to Adapt to New Environmental Threats

Known for their ability to conform to surrounding colors, chameleons represent one of nature's most unusual clades. Indeed, their ability to change color, their individually mobile and stereoscopic eyes, and their parrot-like feet make them distinctive—and desirable—lizards that are also popular pets. In the wild, however, these animals are facing challenges that even they have trouble adapting to.

Chameleons enjoy hot climates and are endemic to the forests and deserts of Africa, Madagascar, Spain and Portugal, and across south Asia to Sri Lanka. In addition, they have been introduced to Hawaii, California, and Florida.

Though the ability to change color can be a useful form of camouflage, researchers believe the primary reason chameleons shift shades is social. The color of a chameleon, then, signals to other chameleons and broadcasts some information about the animal's physiological and psychological state.

The other distinctive feature of chameleons is their pair of independently moving eyes. This allows them to see 360 degrees around their bodies, focus on two different objects simultaneously, or focus both eyes on a single object—like prey—to gain greater depth perception.

Another distinctive feature of chameleons is their feet. The lizards typically posses didactyl feet consisting of five toes. These toes are fused into two groups—one of three toes and the other of two—which creates an ideal appendage for grasping branches.

Yet chameleons are not relegated to climbing trees. Some have adapted to survive in largely treeless deserts, like this Flap-necked chameleon in South Africa.

The final incredible feature of chameleons is their tongue. Used for catching insects for food, chameleons typically have very long tongues—and some have tongues longer than their actual bodies. These long sticky organs move very fast, traveling about 26 body-lengths per second.

One chameleon with an astonishingly long tongue is the Cape dwarf chameleon—its tongue is twice the length of its body. However, the species is endemic to only a small area in and around Cape Town, South Africa, meaning that its conservation status is extremely fragile. Unfortunately, as the habitats of these highly specialized lizards is eroded and fragmented, this is becoming increasingly common.

Though few chameleons are actually considered endangered, most of the 180 known species are threatened. In addition to habitat destruction, a growing international demand for chameleons as exotic pets is undermining species around the world.

Indeed, these unique animals are facing a problem that is all too common across continents and species: A lack of regulation and enforcement necessary to protect a fragile population, even as its only home on the planet is stripped away.