The common name “horny toad” refers to the group of reptiles known as horned lizards, belonging to the genus Phrynosoma. These animals are not true toads, but rather flat-bodied, spiky lizards that share a superficial resemblance to amphibians. Their status in the wild is complex, varying significantly by species and geographic location. While the group is not broadly “endangered” at a federal level, many specific populations have disappeared, and certain species face severe decline across their historical ranges, leading to various state-level protections.
Defining the Horned Lizards
The genus Phrynosoma encompasses approximately 21 species of horned lizards found across North, Central, and South America. The most recognized of these is the Texas Horned Lizard (Phrynosoma cornutum), which is the state reptile of Texas and once ranged widely across the Great Plains. Other species include the Short-horned Lizard (P. douglassii) and the Flat-tailed Horned Lizard (P. mcallii).
These lizards are instantly identifiable by their broad, flattened bodies and the prominent crown of thorn-like projections on the back of their heads. Their defensive adaptations are unique, including the ability to inflate their bodies to appear larger and the capacity to squirt jets of blood from their eyes against predators. Horned lizards are highly specialized insectivores, relying almost exclusively on harvester ants (Pogonomyrmex spp.) for their diet.
Current Conservation Status
The conservation status of horned lizards is a patchwork of concern. Federally, the Texas Horned Lizard (P. cornutum) is not listed under the Endangered Species Act, though it is recognized as a Federal Species of Concern. This designation indicates that the species is experiencing a decline and warrants monitoring but does not provide the full legal protection of an endangered listing.
The most significant protections exist at the state level, reflecting localized losses. For instance, the Texas Horned Lizard is formally listed as a threatened species in Texas, having vanished from almost half of its historical range. In Oklahoma, the species is classified as a “Species of Greatest Conservation Need,” making it illegal to capture, possess, or sell them without a permit. These state-level protections address documented population crashes throughout the eastern and central portions of their former distribution.
Key Factors Driving Population Decline
One of the most significant threats to horned lizards is the loss and fragmentation of their preferred habitat due to human development. Urbanization, agricultural expansion, and the construction of roads have reduced the open, arid, or semi-arid terrain with loose soil that these reptiles require for basking, foraging, and burrowing. The remaining populations are often isolated, making them vulnerable to localized extinction events and reducing genetic diversity.
A powerful biological factor contributing to the decline is the introduction of the non-native Red Imported Fire Ant (Solenopsis invicta). These aggressive invasive ants directly prey on horned lizard hatchlings and eggs, which are defenseless against mass attacks. Furthermore, the fire ants aggressively outcompete the native harvester ants, the primary food source for adult horned lizards, leading to a collapse of the lizard’s specialized diet.
The widespread use of broadcast insecticides to control fire ant populations and other agricultural pests has compounded the problem. These chemicals not only harm the lizards directly but also decimate the harvester ant colonies on which the lizards subsist. Since the lizards cannot easily switch their diet, the loss of their main prey leads to starvation. This disruption of the food web and direct predation by invasive species are primary drivers of the population crash.
Active Recovery and Protection Measures
Conservation efforts for horned lizards, particularly the Texas Horned Lizard, focus on research, reintroduction, and habitat management. Zoos and universities, such as the Fort Worth Zoo and Texas Christian University, operate specialized captive breeding programs. These programs have developed the necessary protocols to raise these lizards and aim to produce large numbers of genetically diverse hatchlings for release into protected areas.
Reintroduction efforts have shifted focus from translocating wild adults, which often suffer high mortality, to releasing captive-raised hatchlings into carefully managed habitats. Biologists recently documented a significant milestone: zoo-raised hatchlings released in 2019 survived long enough to successfully reproduce in the wild. This success provides hope for restoring populations to areas like the Mason Mountain Wildlife Management Area, where extensive habitat restoration has been undertaken.
Land management practices are being adapted to benefit the lizards, including restoring native grasses and utilizing controlled grazing and burning regimens to maintain the open habitat they prefer. Efforts to control invasive fire ant populations focus on targeted bait treatments, avoiding the broad use of harmful insecticides. Continued research into the genetic structure of regional populations helps ensure that reintroduction efforts use appropriate stock to maximize the chances of establishing self-sustaining populations.