Reptiles

Fence Lizard

Sceloporus · also called fence lizards, spiny lizards

Least Concern → insectivore Temperate forest Temperate grassland Desert

A fence lizard is one of the most ordinary-looking reptiles in North America — a small, spiny-scaled lizard doing push-ups on a fence post — and one of the most quietly useful. Ticks that bite it and carry the bacteria behind Lyme disease often come away cured rather than still infectious, a side effect of a protein in the lizard’s own blood.

Overview

Fence lizards are the genus Sceloporus, about 90 species of rough, spiny-scaled lizards across the United States, Mexico, and Central America, from desert scrub to pine-oak mountain slopes. They hunt insects by sight from a favourite perch, and readily use fence posts, walls, and woodpiles, making them one of the most commonly seen reptiles across much of their range.

Push-ups and blue bellies

Males defend territory and court females with a rapid push-up display, showing off bold blue throat and belly patches developed in the breeding season; females and young lack the blue.

An accidental disease fighter

Fence lizard blood carries a protein that kills the Lyme disease bacteria inside ticks that feed on it, rather than the lizard catching the infection. Because fence lizards are a major host for young ticks in parts of their range, abundant lizard populations have been linked in field studies to fewer infected ticks locally.

Status

Least Concern — common and widespread, tolerant of disturbed habitat, and often thriving around the very fences, walls, and woodpiles that give it its name.

Fence Lizard: common questions

Why do fence lizards do push-ups?

The push-up display is a visual signal used mainly by males to defend a territory and to attract females, and by repeatedly bobbing the front of the body up and down while perched in a visible spot, the lizard both advertises its presence and condition to rivals and shows off the blue throat and belly patches that develop in breeding males, making the display serve as both a warning to other males and a courtship signal to females at the same time. The speed and vigour of the push-ups can also communicate the individual's size, fitness, or willingness to defend the territory to a lizard watching from a distance.

How does a fence lizard help reduce Lyme disease?

Fence lizard blood contains a protein that binds to and destroys the Borrelia bacteria responsible for Lyme disease, so when an infected immature tick, commonly the black-legged or deer tick, feeds on a fence lizard's blood, the bacteria in that tick are killed rather than the lizard becoming infected or the tick remaining a carrier. Since fence lizards are a very common host for the larval and nymph stages of these ticks in parts of their range, a high local population of fence lizards has been associated in some field studies with a lower proportion of ticks in the area actually carrying the Lyme disease bacteria, though the overall effect on human infection risk varies with other local factors.

How can I tell a male from a female fence lizard?

The clearest sign is the blue belly and throat patches that develop in breeding males, typically bold blue patches on the sides of the belly and sometimes the throat, often edged with black, which females generally lack or show only faintly. Males also tend to have a slightly larger, more robust build and perform the territorial push-up display far more often and more vigorously than females. Outside of these features, both sexes share the same basic spiny-scaled, greyish or brownish, often faintly barred or striped body pattern typical of the genus.

Are fence lizards good to have around the garden?

Generally yes, since fence lizards are harmless to people and pets, do not damage plants or structures, and feed heavily on insects and other small invertebrates, including some that gardeners consider pests, providing a degree of natural pest control simply by going about their normal hunting from favourite perches. Their habit of basking openly on fences, walls, and woodpiles also makes them one of the more easily observed and appreciated reptiles for people who enjoy watching garden wildlife, and their broader ecological role in possibly reducing the proportion of Lyme-carrying ticks in an area is an added incidental benefit in regions where that tick species occurs.

Sources & further reading

Written by HideShark Editorial Team · reviewed by HideShark Science Desk. Published September 11, 2026. Last updated September 11, 2026.

Quick facts

Scientific name: Sceloporus
Diet: Mainly insects and other small invertebrates including ants, beetles, spiders, and caterpillars, hunted by sight from a favourite perch such as a fence post, log, wall, or tree trunk, with the lizard darting out to seize prey and returning to the same lookout point
Push-ups as a territorial signal: A male fence lizard defends his territory and attracts mates with a distinctive push-up display, bobbing his whole front body rapidly up and down while perched in the open, which shows off the blue or blue-and-black patches on his throat and belly to rivals and potential mates at the same time
Spiny, keeled scales: Fence lizards get the alternative name spiny lizards from their rough, pointed, overlapping scales, each with a raised ridge or keel, giving the skin a bristly texture that helps distinguish the group from the smoother-scaled skinks and whiptails often found in the same habitat
Blue bellies in males: Breeding male fence lizards typically develop bold blue patches on the throat and sides of the belly, sometimes bordered in black, used in territorial and courtship displays, while females and juveniles usually lack the blue and show duller, more camouflaged patterning instead
A lizard whose blood fights Lyme disease: Fence lizard blood contains a protein that destroys the bacteria that causes Lyme disease when a tick carrying it feeds on the lizard, effectively curing infected ticks of the bacteria rather than the lizard catching the disease, and because fence lizards are common hosts for the ticks' immature stages, high fence lizard numbers in an area have been linked in some studies to lower local rates of infected ticks
Around 90 species across the Americas: The genus Sceloporus contains roughly 90 species distributed from the southern United States through Mexico and Central America, occupying a wide range of habitats from dry desert scrub and rocky outcrops to pine-oak woodland and high mountain slopes
Common and highly visible: Fence lizards are among the most frequently seen reptiles across much of their range, basking openly on fence posts, walls, tree trunks, and woodpiles in yards, parks, and farmland, and their willingness to use these human-altered perches has made them one of the more familiar lizards to people who might otherwise rarely encounter reptiles
Range: The southern and western United States through Mexico and Central America, in a wide variety of habitats including desert scrub, chaparral, oak and pine-oak woodland, grassland, rocky outcrops, and mountain slopes, and readily using fence posts, stone walls, woodpiles, and other human structures as basking and lookout perches within these habitats.
Conservation status: Least Concern → ≈ Most fence lizard species are common and widespread across their range and are assessed as Least Concern, tolerating a considerable degree of habitat disturbance and even benefiting from human structures such as fences, walls, and woodpiles that provide basking and lookout perches. A number of species with more restricted ranges, particularly certain mountain, island, or specialised desert populations in Mexico, have smaller distributions and could be more vulnerable to local habitat change, but there is no broad decline documented across the genus, and the eastern and western fence lizards of the United States in particular remain abundant across a large range in the wild