Reptiles
Round-Tailed Horned Lizard
Phrynosoma modestum · also called round-tailed horned lizards
Nearly invisible against a stretch of pale, gravelly desert flat, a round-tailed horned lizard sits perfectly still, its rounder, less spined body relying on camouflage rather than the dramatic flattened silhouette most other horned lizards depend on.
Overview
The round-tailed horned lizard, Phrynosoma modestum, is a small, camouflaged reptile native to open, gravelly desert flats across the southwestern United States and northern Mexico. Its unusually round body shape compared with most other horned lizards, exceptional camouflage against pale desert substrate, and specialised ant-heavy diet make it one of the more visually distinct members of the horned lizard group.
A horned lizard that skipped the horns
While most horned lizards rely on a flattened body and prominent spines, the round-tailed horned lizard takes a subtler approach, blending into the desert floor so effectively that stillness alone does most of the work.
Status
Least Concern — widespread and stable across suitable open, gravelly desert habitat throughout the southwestern United States and northern Mexico.
Round-Tailed Horned Lizard: common questions
How is the round-tailed horned lizard different from other horned lizards?
This species has a notably rounder, less flattened body than most other horned lizard species, with shorter, less pronounced head spines and a rounded rather than flattened tail, relying more heavily on plain camouflage against pale, gravelly ground than on a dramatic flattened silhouette or prominent spines.
What does the round-tailed horned lizard eat?
This species feeds heavily on ants, a dietary specialisation shared broadly across the horned lizard group, supplemented with beetles and other small invertebrates found on the open desert ground it occupies.
Can the round-tailed horned lizard squirt blood from its eyes?
Like several other horned lizard species, this species can, in some individuals and situations, squirt a small stream of blood from the eyes as a startling last-resort defence against a persistent predator, though this dramatic behaviour is not always triggered and appears to be reserved for genuinely serious threats.
Where does the round-tailed horned lizard live?
This species is native to open, gravelly desert flats across the southwestern United States and northern Mexico, favouring pale, sparsely vegetated ground that closely matches its own camouflage colouration.