The Texas horned lizard (Phrynosoma cornutum) is a distinctive reptile recognized by its flat, spiky body and prominent head horns. Often called a “horny toad” or “horned frog,” this true lizard’s unique appearance has made it an iconic symbol of the southwestern United States and Mexico. It holds significant cultural importance, particularly in Texas, where it serves as the official state reptile and is deeply embedded in local folklore. While many Texans recall encountering these lizards, sightings have become increasingly rare. The species is facing significant challenges and is considered threatened in various parts of its historical range.
Current Conservation Status
The Texas horned lizard is not federally endangered across its entire range. However, the Texas Parks and Wildlife Department (TPWD) designates it as a “Threatened Species” within Texas. This designation indicates serious concern for its future, indicating it may become endangered without effective conservation. In Oklahoma, it is classified as a “species of special concern,” where its collection or harm is prohibited.
The species’ status varies across other states within its historical distribution, which once stretched from Arizona to Louisiana and from southern Texas to central Kansas. While it persists in parts of New Mexico, Arizona, Kansas, and Colorado, its populations have declined. A “threatened species” is generally defined as one at risk of extinction, such as vulnerable, endangered, or critically endangered. This status provides legal protections aimed at preventing further population reductions.
Primary Factors Behind Population Decline
The decline of the Texas horned lizard population stems from interconnected environmental changes and human activities. A significant factor is the widespread loss and fragmentation of its natural habitat. Urban expansion, agricultural development, and the construction of infrastructure have converted vast areas of its preferred grassland and scrubland into unsuitable environments, isolating remaining populations. Non-native grasses, often introduced for livestock, can also create dense ground cover that impedes the lizards’ movement and access to soil for burrowing and nesting.
Pesticide use has had a devastating impact on the lizard’s primary food source: harvester ants. Texas horned lizards are dietary specialists, with harvester ants comprising up to 70% of their diet. Broad-spectrum insecticides, used for pest control, directly reduce these ant populations, leading to food scarcity. Additionally, direct exposure to these chemicals can sicken or kill the lizards through bioaccumulation.
The invasion of non-native red imported fire ants (Solenopsis invicta) exacerbates the problem. These aggressive invaders outcompete native harvester ants for resources and space, and their venomous stings can directly attack and kill young horned lizards, which lack evolved defenses. The overall effect on the ecosystem is detrimental to their survival. Road mortality also contributes to population declines, as lizards are frequently run over when crossing paved surfaces. Historically, over-collection for the pet trade also played a role in localized declines, though it is less significant than habitat loss and pesticides today.
Ongoing Conservation Efforts
Numerous initiatives are underway to protect and restore Texas horned lizard populations. A primary focus involves habitat restoration and preservation, including efforts to protect existing suitable habitats and restore degraded areas. This includes managing rangelands to promote native grasses and suitable soil conditions for the lizards and their ant prey.
Research and monitoring programs are vital, with scientists studying the lizards’ ecology, population dynamics, and specific threats to inform conservation strategies. Citizen science programs, like the Texas Horned Lizard Watch, engage the public in reporting sightings, which helps track distribution and population trends. Captive breeding and reintroduction programs, notably at institutions like the Fort Worth Zoo, San Antonio Zoo, and Caldwell Zoo, are actively breeding lizards in controlled environments. These zoo-hatched lizards are then carefully released into protected wild areas that have undergone habitat preparation, with continued monitoring to assess their survival and reproduction. Public awareness and education campaigns inform people about the lizard’s plight and the importance of conservation.
How You Can Contribute to Protection
Individuals can make a tangible difference in the protection of the Texas horned lizard. Supporting conservation organizations dedicated to the species through donations or volunteering helps fund research, habitat restoration, and reintroduction programs. Organizations like the Horned Lizard Conservation Society welcome public involvement.
Responsible pesticide use at home and in gardens is another direct way to help. Avoiding broad-spectrum insecticides, especially those that harm harvester ant populations, protects the lizards’ food source. If pest control is necessary, targeted treatments are preferable to widespread application. Creating wildlife-friendly yards by maintaining natural vegetation and avoiding chemical use can also provide suitable microhabitats. Reporting sightings of Texas horned lizards to state wildlife agencies or citizen science platforms contributes valuable data for monitoring efforts, helping researchers understand population dynamics and distribution. Never attempt to capture or keep them as pets.