Overview
The Keeled Earless Lizard (Holbrookia propinqua) is a specialized, fast-running reptile native to the sun-bleached coastal dunes and sandy barrier islands of the Gulf of Mexico. Characterized by keeled, overlapping dorsal scales and the complete absence of external ear openings, it is an iconic inhabitant of Padre Island National Seashore.
Biology and Physical Characteristics
The Keeled Earless Lizard is distinguished from other earless lizards by its longer, more slender tail and distinctly keeled dorsal scales. Its dorsal coloration is pale yellowish-tan or light grey peppered with small dark spots that blend seamlessly with crushed shell and maritime sand. Breeding males display bright turquoise-blue and vivid yellow washes on their flanks with paired dark diagonal belly bars.
Behavior and Ecology
An exceptionally fast and agile runner, the Keeled Earless Lizard darts between sea oats and coastal morning glory vines on beach dunes. When surprised on open sand, it curls its tail upward over its back, displaying the clean white underside before sprinting to a nearby vegetation clump or diving headfirst into loose maritime sand to vanish beneath the dunes.
Conservation and Human Impact
Categorized as Least Concern by the IUCN, the Keeled Earless Lizard is abundant on undeveloped barrier island stretches along the Texas and northern Mexican coasts. It faces localized pressures from coastal real estate development, vehicular traffic on beaches that crushes burrows, and storm surge flooding during intense hurricanes.
Interesting Factoid
The Keeled Earless Lizard thrives right alongside ocean waves on Gulf Coast beaches, dashing across the hot sand like a tiny feathered dinosaur to snatch up amphipods and sand fleas washed up by the tide.