The common chuckwalla, native to the Mojave Desert of North America, is the second largest species of lizard found in the United States.
Chuckwallas, spelled chuckawallas at times, are large lizards native to the arid regions of the United States and Mexico. They belong to the genus Sauromalus of the Iguanidae family of lizards. (The word Sauromalus is derived from ancient Greek words ‘sauros‘, meaning lizard, and ‘omalus‘, meaning flat.)
There are five species of chuckwallas in the world, namely the Common chuckwalla (Sauromalus ater), Peninsular chuckwalla (Sauromalus australis), Angel Island chuckwalla (Sauromalus hispidus), Montserrat chuckwalla (Sauromalus slevini), and the San Esteban chuckwalla (Sauromalus varius). Of these, only the common chuckwalla is found in the Mojave and Sonoran deserts.
Habitat: This chuckwalla species is found in abundance in the Mojave Desert, spanning California, Nevada, Utah, and Arizona in the United States. Most often dwelling in rocky areas, these lizards are also known to inhabit burrows of dirt, especially in case of loss of natural habitat.
Appearance: These large, flat-bodied lizards have a rounded belly and a tail with wide base and blunt tip. They can grow up to a length of 16 inches and weigh around 2 lbs. They sport loose folds of skin around their necks. Their body is covered with small scales, which acts as a protective covering. In males, the head, upper trunk, and forelegs are black in color, with a hint of reddish-yellow on the mid-body. In contrast, females are gray or brown in color, with scattered red spots.
Dietary Habits: Chuckwallas are mostly herbivores by nature, feeding on flowers, such as brittle bush, and leaves. However, it is also observed that occasionally, these lizards also feed on insects. Common chuckwallas can also climb trees to reach flowers.
Behavior: Being diurnal in nature, these lizards are mostly active during the day and take rest at night. These exothermic creatures spend the morning basking in the hot sun. Large outcrops or piles of boulders are typical basking sites for these lizards. Chuckwallas communicate through series of actions, like head bobbing and gaping.
Adaptations: As with various other animals found here, even chuckwallas resort to typical desert animal adaptations to survive the arid conditions and stay active when the temperature reaches as high as 102°F. During the winter, however, these lizards go into hibernation, only to return in warmer time of the year.
Reproduction: Territorial males dominate other smaller males in their territory, especially during the mating season. Mating takes place between April and July. The female lays around 5 to 15 eggs, which hatch in late September or early October.
Relationship with Humans and Other Species: These shy creatures run away from potential dangers and hence, are never considered a threat for humans. They escape into rock crevices at the slightest sense of danger. When predators attempt to pull them out, they firmly grip the walls of the crevice, with their rough scales and strong claws. They can also inflate their bodies to tighten their hold.
The native Americans used to kill these lizards for food. A specially designed tool, made of stone and stick, was used to pull them out from the rock crevices. Found in abundance, the common chuckwalla is enlisted as one of the Least Vulnerable species on the planet by the International Union for the Conservation of Nature (IUCN).