Eastern Fence Lizards (Sceloporus undulatus) are common reptiles found across diverse environments in eastern North America, from New York south to Florida and west to states like Ohio and Arkansas. These adaptable lizards inhabit various landscapes, including woodlands, grasslands, and suburban areas. While often spotted basking on fences or logs, their diet reveals them to be primarily insectivorous predators.
The Primary Diet
The bulk of an Eastern Fence Lizard’s diet consists of various insects and other small arthropods. Ants, which can constitute a significant portion, up to 80%, of a juvenile’s diet. Other frequent meals include beetles, like wood-boring, ground, and leaf beetles, along with weevils, spiders, and grasshoppers. Moths, crickets, stink bugs, flies, and caterpillars also regularly feature in their diet.
These lizards are opportunistic, consuming a wide variety of small invertebrates they encounter. Their diverse palate ensures they receive a range of nutrients, contributing to their overall health. Female Eastern Fence Lizards exhibit a notable increase in food consumption during the spring months, as they require additional energy and nutrients for egg production.
Occasional Dietary Additions
While insects form their main diet, Eastern Fence Lizards may occasionally supplement their meals with other small organisms. Snails are sometimes consumed. In rare instances, these lizards may prey upon very small vertebrates, including other tiny lizards.
Plant matter is generally not a deliberate part of their diet; Eastern Fence Lizards are primarily insectivores and their digestive systems are not well-suited for processing vegetation. Any ingestion of plant material, such as needlegrass or cheatgrass, is typically accidental, occurring when they are capturing insect prey.
Foraging Behavior and Habitat Influence
Eastern Fence Lizards employ a “sit-and-wait” foraging strategy, making them ambush predators. They often perch in sunny locations like fences, logs, rocks, or tree trunks, patiently observing their surroundings. Their keen eyesight is their primary tool for detecting prey, allowing them to quickly capture unsuspecting insects that pass by.
These lizards typically forage twice a day, often in the morning and early evening. The types of prey available to them are directly influenced by their habitat, which can range from open woodlands and forest edges to suburban yards with ample hiding and basking spots. Seasonal shifts also impact their diet, with a greater abundance of certain insects leading to increased consumption during specific times of the year.