Common Five-lined Skink

Overview

The Common Five-lined Skink (Plestiodon fasciatus), widely celebrated throughout eastern North America as the blue-tailed skink, is one of the most familiar, abundant, and visually striking squamates native to temperate hardwood woodlands. Renowned for its spectacular ontogenetic color transformation, juvenile skinks boast an electric cobalt-blue tail that glimmers like neon against glossy jet-black bodies lined with five crisp, white-to-yellow stripes. Darting with lightning speed across sunlit rotting logs, stone foundations, and weathered woodpiles, this agile scincid is a quintessential symbol of the eastern forest understory.

Ecologically, Plestiodon fasciatus occupies an essential predatory niche on the forest floor, acting as an agile consumer of terrestrial arthropods, wood-boring beetle larvae, spiders, and termites. By hunting actively within dead fallen timber and decomposing leaf mulch, skinks accelerate the biological breakdown of decaying wood and control pest populations. Additionally, the common five-lined skink exhibits rare and sophisticated maternal care behaviors among lizards: female skinks meticulously brood, turn, and defend their clutches of eggs until hatching, ensuring high offspring survival across damp temperate microhabitats.

Biology and Physical Characteristics

The morphology of Plestiodon fasciatus is characterized by sleek, smooth, overlapping cycloid scales that impart a polished, glass-like texture, minimizing friction during rapid dashes into tight rock crevices and log hollows. Adult coloration exhibits pronounced sexual dimorphism: while females largely retain the five distinct longitudinal yellowish stripes against a dark brown ground with a faded bluish-grey tail, breeding adult males undergo a striking transformation, with their stripes fading to a uniform olive-brown while their jaws and snout develop a fiery, swollen orange-red breeding coloration. The electric-blue tail of juveniles serves as a deceptive decoy: if attacked by a bird or small mammal, the skink executes caudal autotomy, shedding the thrashing, brightly colored tail to distract the predator while the lizard slips away.

Behavior and Ecology

Common five-lined skinks are diurnal, alert heliotherms that emerge on sunny mornings to bask on exposed fallen logs, tree trunks, and wooden fence rails until their body temperatures reach approximately 32°C (90°F). Foraging is active and chemosensory-driven; the skink frequently flicks its dark tongue to sample airborne and substrate chemical cues, tracking down hidden spiders and beetles inside rotted timber. In early summer, females excavate small nesting cavities within damp, decaying logs, laying 4 to 14 parchment-shelled white eggs. The mother remains curled around her clutch for over a month, actively grooming the eggs with tongue flicks to remove fungal spores, rolling them to ensure uniform development, and retrieving eggs that accidentally roll out of the nest.

Conservation and Human Impact

Plestiodon fasciatus is designated as Least Concern by the IUCN, remaining common and widely distributed across much of the eastern United States. However, northern peripheral populations in Southern Ontario, Canada, represent isolated, fragmented remnants that are officially protected as species-at-risk under provincial and federal legislation. The primary anthropogenic threats include the removal of dead woody debris from forests during intensive logging, habitat fragmentation from road networks, and predation by domestic cats in suburban woodlots.

Interesting Factoid

If a predator attacks a young five-lined skink, its neon-blue tail snaps off cleanly and violently thrashes and flips around on the ground for several minutes, completely mesmerizing the predator while the lizard silently escapes to safety.