The Texas horned lizard, often affectionately known as the “horny toad,” is an iconic symbol in Texas. Its unique appearance, with a flat body and prominent cranial spikes, makes it recognizable. Many Texans recall encountering these reptiles, prompting concern about their current presence and conservation status.
Conservation Status
The Texas horned lizard (Phrynosoma cornutum) is officially listed as a threatened species by the state of Texas. This designation means the species is likely to become endangered in the foreseeable future if protective measures are not taken. While the International Union for Conservation of Nature (IUCN) classifies the species as “Least Concern” globally, its populations within Texas have experienced severe declines. Collecting, possessing, transporting, or selling Texas horned lizards without a special permit is illegal in Texas.
Historically, the Texas horned lizard ranged extensively across the south-central United States, from southern Arizona to northwestern Louisiana and and from southern Texas to central Kansas. However, its distribution within Texas has significantly fragmented and contracted over recent decades. The species has disappeared from the eastern third of Texas and shows declining population densities in other regions. Conservation records indicate a decline of approximately 30% in the population over the last decade.
Reasons for Decline
The decline of Texas horned lizard populations is attributed to environmental pressures. Habitat loss and fragmentation, driven by urbanization and agricultural development, reduce the open, arid habitats these lizards require for foraging, burrowing, and breeding. Non-native grasses, like Coastal Bermudagrass, further degrade habitat by creating dense thickets unsuitable for lizard movement and hunting.
Widespread use of broad-spectrum pesticides is another significant threat. These chemicals directly reduce populations of harvester ants, which constitute up to 69% of the adult horned lizard’s diet. Without this primary food source, lizards face starvation or must emigrate. The invasion of aggressive, non-native red imported fire ants also severely impacts horned lizards.
Red imported fire ants outcompete native harvester ants for food and space, further depleting the lizards’ food supply. Fire ants can also directly prey on Texas horned lizard eggs and hatchlings, reducing reproductive success. While adult horned lizards are resistant to harvester ant venom, they have not evolved defenses against fire ant venom. Historically, over-collection for the pet trade also contributed to population reductions, though this practice has largely ceased due to protective legislation.
Ongoing Conservation Initiatives
State agencies, universities, and conservation organizations are actively engaged in efforts to protect and restore Texas horned lizard populations. Captive breeding programs are underway at facilities like the Fort Worth Zoo and the San Antonio Zoo’s Center for Conservation & Research (CCR). These programs aim to produce healthy hatchlings for reintroduction into suitable habitats within their historical range. The San Antonio Zoo, for instance, has released nearly 200 zoo-hatched lizards, partnering with private landowners to identify and prepare release sites.
Reintroduction efforts involve careful site selection and post-release monitoring, sometimes utilizing specialized conservation dogs to track lizards. Habitat restoration projects focus on re-establishing native grasses, implementing controlled grazing, and fostering existing harvester ant mounds. These initiatives create environments that can sustain lizard populations. Scientific research continues to enhance understanding of horned lizard ecology, genetics, and optimal conservation strategies. Researchers are studying factors like genetic diversity between northern and southern populations and developing methodologies for successful reintroductions.
Supporting Horned Lizard Recovery
Individuals can contribute to the recovery of Texas horned lizards by making informed choices. Promoting native plant landscaping helps support healthy populations of harvester ants, the lizards’ primary food source. Avoiding broad-spectrum pesticides is also important, as these chemicals harm beneficial insect populations. If fire ant control is necessary, spot treatments are recommended over broadcast applications.
Participating in citizen science programs offers a direct way to aid conservation. Reporting Texas horned lizard sightings to the Texas Parks and Wildlife Department or platforms like iNaturalist provides valuable data for tracking population trends and distribution. This information helps conservationists understand where lizards are thriving and where interventions may be needed. Supporting conservation organizations, such as the San Antonio Zoo, Fort Worth Zoo, or the Horned Lizard Conservation Society, through donations or volunteer work, helps fund research and reintroduction initiatives.