Horned lizards, commonly known as “horny toads,” are reptiles found predominantly in the arid and semi-arid regions of North and Central America. They are recognized by their distinctive flattened, rounded bodies and prominent, horn-like spines on their heads, which are extensions of their skulls. Their coloration features earthy tones like browns, tans, and reddish hues, allowing them to blend seamlessly into their desert and grassland environments. This specialized appearance hints at an equally specialized diet, central to their survival.
The Mainstay of Their Diet
The primary food source for many horned lizard species is ants, making them specialized ant-eaters, a dietary habit known as myrmecophagy. Ants are an abundant and reliable food source in the horny toad’s natural habitat, occurring in concentrated populations, particularly around their nests. Harvester ants (genus Pogonomyrmex) are a favored food item for several species, including the Texas horned lizard (Phrynosoma cornutum), where they can constitute up to 90 percent of their diet.
Consuming ants, which are small and contain much indigestible chitin, necessitates a specialized digestive system. Horned lizards possess a large stomach for their body size; some species, like the desert horned lizard (Phrynosoma platyrhinos), have a stomach that can account for approximately 13 percent of their total body weight. This allows them to consume large quantities of ants. Horned lizards have also developed a resistance to ant venom, enabling them to consume these insects despite their defensive capabilities.
Other Dietary Components
While ants form the bulk of their diet, horned lizards also opportunistically consume other small invertebrates. These supplementary food sources provide dietary variation and are often sought when ant populations are less abundant. Examples include termites, beetles, grasshoppers, and occasionally spiders.
The specific types of supplementary prey can vary depending on the horned lizard species and the availability of insects in their particular environment. This dietary flexibility allows them to adapt to fluctuations in their primary food source, ensuring a broader range of available nutrients.
How They Capture Their Prey
Horned lizards employ an ambush predation technique. Instead of actively pursuing prey, they wait for insects to come within striking distance. Their flattened bodies and cryptic coloration allow them to blend seamlessly with the surrounding soil and vegetation, making them difficult for prey to detect.
Once an insect is close enough, the horned lizard swiftly extends its sticky tongue to capture it. This rapid tongue flick allows them to snatch insects before the prey can react. Their ability to minimize movement and blend into their surroundings helps them conserve energy while foraging.