Date: 5/7/07
Contact: Margie Klein
Phone: (702) 486-5127, ext. 3502

LIZARD TAILS (LIZARD TALES)

A sure sign that the warm weather has hit the Mojave Desert is the sight of lizards which are commonly seen soaking up warmth from the springtime sun. Nevada Department of Wildlife Reptile Biologist Polly Conrad begins her diurnal (daytime) lizard surveys as early as March or April each year and tries to wrap them up by July before the extreme temperatures hit.

Even though lizards have adapted to the desert climate, lizards can still fall victim to overheating if they cannot move to a cooler location and regulate their body temperature. Conrad doesn’t want any of the lizards to get superheated in the pitfall traps she uses to catch her specimens. She checks her traps early in the morning so she can release any captives before it gets too hot. The lizard surveys are a yearly occurrence statewide, and give biologists a good idea of the number and species that are present in the sampled areas.

One of the anomalies that Conrad has seen on her surveys is a two-tailed, Great Basin whiptail lizard found during a 2007 survey. “Whiptails are one of the fastest lizards in southern Nevada,” Conrad said, especially when they drop their tail to get away.

This two-tailed oddity had grown in a new tail right next to the long stump of the sloughed-off one. Most lizards have this adaptation of dropping their tail as a means of getting away from a predator. The tail breaks off at a natural weak point in the tail vertebrae. Kids who grow up in the desert know that when they catch a lizard with their hand, they are often left holding just the tail. Sometimes the tail piece is left twitching, which distracts the predator while the lizard runs to safety.”

Lizard tails are used for balance and locomotion, to play a part in social status and in some species to store fat reserves. The regrowth of the tail is costly - with all the animal’s energy being directed toward the new growth, any other growth as well as reproduction slows down temporarily. Regenerated tails have no cartilage or bones, and they do not always have the color and markings of the original. They can, however, be detached again.

Depending on their need, other desert lizards may or may not use this tail-dropping defense. Horned lizards, sometimes called horny toads, have a relatively short tail and don’t usually need to drop it because of another defense mechanism that works equally well – they shoot blood out of their eyes. The banded gecko emits a high-pitched squeak as its first defense strategy, but they are also very quick to discard their tails.

The collared lizard has a sturdy tail that is rarely lost. This species will bite if captured. And finally, the Gila monster does not lose its tail, as that could mean certain death. Gila monsters have very large, thick tails which can store enough fat for the animal to survive for a year or more. Gila monsters are venomous and have a tenacious bite they will use to defend themselves, so people should do not handle them. The sight of any of these lizards is a happy occurrence, so try to catch a glimpse of them before they high-tail it away.

The Nevada Department of Wildlife (NDOW) protects, restores and manages fish and wildlife, and promotes fishing, hunting, and boating safety. NDOW's wildlife and habitat conservation efforts are primarily funded by sportsmen's license and conservation fees and a federal surcharge on hunting and fishing gear. Support wildlife and habitat conservation in Nevada by purchasing a hunting, fishing, or combination license. For more information, visit www.ndow.org.