Sceloporus undulatus
fence lizard

Eastern fence lizards range from mid New York south to mid Florida and northern part Texas and as far west as Colorado.

Subspecies include: southern fence lizards, S. u. undulatus, southern prairie lizards, S. u. consobrinus, White Sands prairie lizards, S. u. cowlesi, northern plateau lizards, S. u. elongatus, red-lipped prairie lizards, S. u. erythrocheilus, northern prairie lizards, S. u. garmani, northern fence lizards, S. u. hyacinthinus, and southern plateau lizards, S. u. tristichus. (Bishop, 1941)

Eastern fence lizards are found in grasslands, shrublands, and the edges of pine or hardwood forests. Eastern fence lizards live under wood piles, logs, and rocks where they can be protected during the evening hours. During daylight hours eastern fence lizards can be found basking in the same areas in which they rest: on fences, logs, rock, and tree trunks. (Behler, 1979; Bishop, 1941; Kennedy, 1958)

Eastern fence lizards vary in color geographically, but are usually gray, brown or a rusty color. Males and females are similar in size. Individuals in northern populations (northern New York south to Maryland) are generally smaller than individuals in southern populations (northern Virginia south to northern Florida). This may be because southern populations have a longer warm season in which to eat and grow.

Males have a blue patch on the belly and throat. Average adult mass is 15 g, while adult total lengths range from 9 to 19 cm. (Angilletta, 2001; Behler, 1979; Johnson, 1966; The University of Chicago, 1992)

After being laid, eggs double in size during embryonic development. Eggs hatch from June to September. Upon hatching, individuals are about half the size of adults. They tend to grow quickly in the first two months of life and are fully mature at 1 year. (Bishop, 1941; Ferguson, Bohlen, and Woolley, 1980; Smith, 1946)

Lifespans of eastern fence lizards are not well understood, but researchers believe that they can live for more than 5 years, possibly averaging ages of 4 years. However, the majority of eastern fence lizards probably die soon after hatching. (Haenel and John-Alder, 2002; Smith, 1946)

Fence lizards are active during the day, from 0600h - 2000h, basking in the sun on wood piles, fence posts and trees. During the summer months the use of rock perches decreased while the use of tree trunks and branches increased. This allows them to maintain their temperature as the season gets hotter. They tend to choose more closed surroundings than other lizards.

Their sleeping location is very close to, if not at, their basking locale. This site is usually selected based on temperature and relative protection from predators.

Males flash their blue patch, as well as exhibit head-bobs and push-ups, in order to let other males know that this is his territory. Territory seems to be correlated directly to the availability to food as well as the presence and varations of other lizard species in the area. (Angert et al., 2002; Angilletta, 2001; Kennedy, 1958; Mitchell, 1994; Presidents and Fellows of Harvard College, 1983; The University of Chicago, 1992)

Home Range

Fence lizards have a very defined home range, ranging from 47 - 61 square meters. During years when food is plentiful, their home range increases. (Kennedy, 1958; Presidents and Fellows of Harvard College, 1983)

To attract mates and warn off other individuals, male eastern fence lizards do head bob displays, push ups, and puff themselves up. Head-bobs and push-ups are done in 4 to 5 second durations. (Mitchell, 1994)

Eastern fence lizards eat primarily insects and other arthropods, including ants (Formicidae), beetles (Coleoptera), weevils (Curculionidae), lady bugs Coccinellidae), spiders (Araneae), and centipedes (Chilopoda). They also sometimes eat snails (Gastropoda). Some plant matter like cheatgrass (Bromus tectorum) and needlegrass (Caproni stipa) is sometimes consumed. Females tend to eat more insects during the spring months, in order to save energy for egg-laying. Lizards generally forage twice daily. (Behler, 1979; Johnson, 1966)

Males with larger blue patches are more likely to be preyed on by birds. As a result, males have a high mortality rate during early spring when they are establishing mating territories. Females have a higher mortality rate during the period of egg-laying, because they are protecting their territory, making them more susceptible to predators. Larger lizard species, snakes, and domestic cats and dogs also eat eastern fence lizards. Eastern fence lizards are slower than other lizards, often giving predators. Eastern fence lizards are cryptically colored and can move quite rapidly when they are warm. (Angert et al., 2002; Mitchell, 1994; Presidents and Fellows of Harvard College, 1983; The University of Chicago, 1992)

Eastern fence lizards mainly feed on insects and are themselves prey for birds and other larger predators. They compete with other lizard species for their insect prey. Common parasites include chiggers and botflies. (Angert et al., 2002)

Eastern fence lizards are not pests and do not have a negative effect on the human population. If individual lizards are harassed, they may bite. (Angilletta, 2001)

Eastern fence lizards are used to help educate people about conservation and reptiles. Eastern fence lizards decrease insect and arachnid populations, which can be pest species in some areas. (Mitchell, 1994)

Eastern fence lizards are thriving due to the availability edge habitats and secondary growth around pine forests, their preferred habitat. (Mitchell, 1994)

Flooding can have a disastrous effect on eastern fence lizard hatchling populations. (Behler, 1979; Pinch and Claussen, 2003)