Gerrhonotus infernalis
Silhouette: SeismicShrimp · PhyloPic
In 3 days ~60% in a week ~90%
The Texas alligator lizard (Gerrhonotus infernalis) is a species of lizard in the subfamily Gerrhonotinae of the family Anguidae. The species is endemic to the central region of the American state of Texas, and south into adjacent northern Mexico.
The Texas alligator lizard is a medium-sized lizard, attaining a maximum total length (including tail) of around 24 to 25 in (61 to 64 cm). It is the largest lizard species in Texas, and one of the largest alligator lizards in the world. This lizard has a flat, wedge-shaped head. Its body is generally a yellow-brown color, often with darker brown and white checker patterning on its dorsal surfaces, and uniformly light-colored, white, or grey on its ventral surfaces. Its scales are very stiff and plate-like. It has short limbs, and a tail that can fall off to distract a potential predator, but will regrow in time.
Errhonotine lizards are known for their broad heads, short limbs and being heavily armored with scales, from which the common name alligator lizard derived. Gerrhonotus liocephalus, in particular, can be easily recognized by 16 longitudinal rows of dorsal scales and 46 to 54 dorsal scales from the occiput to the... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Big Bend National Park | 🇺🇸 United States | |
| 2 | Cumbres de Monterrey National Park | 🇲🇽 Mexico |
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | Fort Worth Zoo | 🇺🇸 United States |
No species of the same family or order lives in Big Bend National Park, so these are its closest relatives here: other reptiles.
Possible
About 20% of wildlife watchers report a Texas Alligator Lizard sighting in Big Bend National Park on a given day, based on 72 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 11th most-seen of the 48 reptiles we can rate there. Over three days the chance rises to about 60%, and over a week to about 90%, if each day is a fresh chance.
September
In that month about 50% of wildlife watchers report a Texas Alligator Lizard in Big Bend National Park on a given day, against under 5% in January, the lowest month. That is one of Big Bend National Park's wettest months, with about 50 mm of rain against 10 mm in April.
Between 9 am and noon
Across all the parks we cover, that three-hour window holds the most Texas Alligator Lizard sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Yes
Of the 2 parks where we can rate Texas Alligator Lizard sightings, Big Bend National Park has the highest daily chance: about 20%. Next come Cumbres de Monterrey National Park (Mexico, about 20%).
GBIF citizen-science records
It is estimated from how often the Texas Alligator Lizard is recorded against all the reptiles logged in Big Bend National Park (72 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
