Lizards

Pest Notes: Introduction

Lizards are common reptiles that mostly feed on insects. They can be fascinating creatures to watch, but trying to maintain them in captivity for any great length of time can be difficult. Many lizards will attempt to bite if roughly handled, and their small, sharp teeth may puncture the skin. Otherwise, most of them are completely harmless to people. The only venomous lizard in the entire United States is the Gila monster, which is found only in the desert regions of the southwest and is uncommon in Southern California. On rare occasions, lizards may enter a home or garage and cause concern.

Identification and Biology

Lizards are the most abundant of the reptiles, comprising nearly 6,000 species worldwide and over 60 types in California. They are usually recognized by their dry, scaly skin, four legs with clawed feet, and external ear openings. Unlike snakes, which are legless, most lizards run over the ground. Another difference between common snakes and lizards is the eye. Most lizards have eyelids that close over the eyes, whereas most local snakes do not have movable eyelids. There is one genus of lizard along the central coast of California that does not have legs, but these lizards still have eyelids (genus Anniella).

The most commonly encountered genus of lizards in California is Sceloporus, including the western fence lizard, S. occidentalis, sometimes commonly called the blue belly lizard. This lizard is one of the quickest and most versatile of the reptiles. It is also one of the most easily seen. During its active period from April to October, it frequents rocks, trees, fences, and buildings. These lizards are 6 to 9 inches long and olive, brown, or black with a pattern of paired blotches or wavy cross bars or stripes down the back. The name “blue belly” comes from the blue patches on the sides of the belly. The adult male also has blue patches on the throat. By flattening his sides and raising his head the male shows his blue markings to announce his presence and frighten away other males.

A common foothill resident is the alligator lizard, genus Elgaria (formerly called Gerrhonotus), that is 8 to 13 inches long and yellowish-green to olive brown. These lizards are primarily found in forested areas at elevations of 1,000 to 11,000 feet. They are not territorial and have a home range of 1 to 2 acres. In contrast to their common name, they are not closely related to alligators and are in fact a generally harmless lizard.

Although some lizards eat plants, most lizards feed on insects. In California, the most common types feed on beetles, ants, wasps, aphids, grasshoppers, and spiders. Lizards cause no measurable damage to plants in gardens and may be beneficial by eating pest insects and should be left alone.

Lizards are generally egg layers; however some species of horned lizards (horned “toads”) and the northern alligator lizard produce their young alive. The most common species of lizard in California, the western fence lizard, lays 3 to 20 cream-colored, soft-shelled eggs in pits of damp soil. Eggs are generally laid from May to August, and the young typically hatch from July to September. Lizards rely on their environment to warm themselves and hibernate during winter months.

An interesting trait of lizards is their ability to lose their tails when handled roughly or pursued by an enemy. The separated tail continues to wriggle while the rest of the lizard escapes. This seems to be a method of self-defense and does no particular harm to the lizard. In time, a new tail will usually grow back.

Legal Status

The taking and possession of lizards is regulated by the California Department of Fish and Wildlife, with specific regulations depending on the species. Although a few lizard species are protected by law, many species may be kept and possessed if you own a current California Freshwater Sport Fishing License. No native lizards can be sold or used for commercial purposes. For further information about taking and possession of lizards contact your local Fish and Wildlife warden or visit the California Department of Fish and Wildlife website to view current regulations.

Management

Occasionally, lizards can enter homes and buildings through small openings, especially gaps beneath doors. They are excellent climbers so they can enter at any structural opening 1/4 inch or larger.

Should a lizard enter your home, there are several ways to capture and release it outdoors. None of the methods is easy; so once the lizard is relocated outdoors make sure it can’t reenter the home (see section below).

Trapping

For the adventurous, there is a method known as “noosing.” Noosing involves using a pole such as a fishing rod to slip a noose over the lizard’s head and gently tightening the noose to capture the lizard, which can then be safely carried outdoors and set free. This method requires a degree of skill because the noose must be slowly lowered over the lizard’s head and then quickly but gently tightened by lifting the lizard with the pole before it escapes. Nooses can be made out of relatively stiff materials like dental floss or fish line.

Another way to trap a lizard is to carefully put a small box or other container over it. With the lizard in the box, gently slip a piece of cardboard under the box to cover the opening. Pick the entire unit up and take it outside to be released.

Alligator lizards move somewhat slower than western fence lizards and often can just be grabbed gently by hand and taken outdoors. Because an alligator lizard may bite, you can wear a glove when you grab it.

Exclusion

To prevent lizards from entering the home, seal all small openings 1/4 inch and larger. Check areas such as corners of doors and windows, around water pipes, electrical service entrances, ventilation screens, water pipes, etc. Threshold sweeps and tight-fitting door seals with no gaps at the edges are important prevention measures. Unlike rats and mice, lizards cannot gnaw through wood or other common building materials. A number of materials can be used to seal access points, including insulating foam, caulking, flashing, and steel wool.

Good sanitation can be helpful in reducing the number of lizards around a home, although it alone will not eliminate their presence. Off-the-ground storage of lumber, crates, boxes, sacks, gardening equipment, and other household items will make an area less suitable for lizards by reducing their hiding spots.

Other Control Methods

There are no toxicants or repellents registered in California that can be used to kill or repel lizards.