Overview
The Mojave Fringe-toed Lizard (Uma scoparia) is a charismatic sand-dune specialist endemic to the isolated blowsand dune fields of the Mojave Desert. Renowned for the remarkable comb-like fringe of scales along its hind toes that allow it to sprint across scorching, loose sand without sinking, it is an evolutionary masterwork of extreme desert adaptation.
Biology and Physical Characteristics
Uma scoparia has a flattened, aerodynamic body decorated with an intricate dorsal lattice of black and brown circular spots, crescent bars, and dark blotches over a pale grey-tan ground color matching windblown quartz sand. It features two prominent crescent-shaped black marks on each side of its belly. Its nostrils have internal sand-excluding valves, and its eyelids have interlocking fringe scales to keep out blinding dust.
Behavior and Ecology
When threatened by predators like kit foxes or hawks, this lizard sprints across sheer dunes at tremendous speeds on its fringed toes before performing a dramatic headlong dive directly into the sand. Using rapid lateral undulations of its body and tail, it ‘swims’ beneath the surface in the blink of an eye, burying itself inches deep in cool, insulated sand layers.
Conservation and Human Impact
Assessed as Least Concern by the IUCN, the Mojave Fringe-toed Lizard remains common across major protected dune fields like Kelso Dunes inside Mojave National Preserve. However, isolated populations outside park boundaries face threats from renewable energy projects, off-highway vehicle (OHV) recreation, and invasive weeds that stabilize and destroy open sand dunes.
Interesting Factoid
The Mojave Fringe-toed Lizard can run across boiling 140°F dunes at 15 miles per hour and then dive headfirst into the sand, ‘swimming’ underground like a fish in water to escape the heat.