The eastern fence lizard is a medium-sized species of lizard in the familyPhrynosomatidae. The species is found along forest edges, rock piles, and rotting logs or stumps in the eastern United States. It is sometimes referred to as the prairie lizard, fence swift, gray lizard, northern fence lizard or pine lizard. It is also referred to colloquially as the horn-billed lizard.
Taxonomy
The generic name, Sceloporus, is derived from the Greekskelos/σκελος, meaning "leg", and the Latinporus, meaning "hole", referring to the enlarged femoral pores found in this genus of lizards. The specific name, undulatus, is Latin for "wave", referring to the transverse dark crossbars on the backs of these lizards. Until 2002, 10subspecies of S. undulatus were recognized, but re-evaluation showed paraphyly between the subspecies. These were reclassified as four distinct evolutionary species. The narrowed redefinition of S. undulatus has been suggested to still contain two subspecies divided by the Appalachian Mountains. None is currently formally recognized. The following cladogram is based on Leaché and Reeder, 2002:
The eastern fence lizard can grow from 4.0 to 7.5 inches in total length. It is typically colored in shades of gray or brown, and has keeled scales, with a dark line running along the rear of the thigh. A female is usually gray and has a series of dark, wavy lines across her back. The belly is white with black flecks, with some pale blue on the throat and belly. The male is usually brown, and during the summer, has a more greenish-blue and black coloration on the sides of the belly and throat than the female. The young look like the females, but are darker and duller. They closely resemble the western fence lizard, but differ slightly in coloration and live in a different area and habitat.
Within the past 70 years, according to a study published in 2009, eastern fence lizards in parts of their range have adapted to have longer legs and new behaviors to escape the red imported fire ant, which can kill the lizard in under a minute. Red imported fire ants threaten eastern fence lizards because they occupy their microhabitats causing mortality or relocation. Moreover, according to a study published in 2016, artificial eastern fence lizard nests were shown to be vulnerable to predation by red imported fire ants, resulting in nonviability of the eggs.
Mating
Eastern fence lizards mate in spring, and lay 3 to 16 eggs in late spring or early summer. The young hatch in summer and fall. Male fence lizards often do "push-ups" to attract mates and to warn other males encroaching on their territory.
