---
title: "What the sources say about the Texas Horned Lizard | AnimalTracks.wiki"
description: "47 claims from the Texas Horned Lizard profile, each beside the words of the source that backs it."
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# What the sources say about the Texas Horned Lizard (*Phrynosoma cornutum*)

> 47 claims from the Texas Horned Lizard profile, each beside the words of the source that backs it. A "..." marks a cut in a quote and [brackets] an insertion.

Profile: [Texas Horned Lizard](https://animaltracks.wiki/animals/texas-horned-lizard/)

## Phrynosoma cornutum (Texas horned lizard). Animal Diversity Web, University of Michigan.

https://animaldiversity.org/accounts/Phrynosoma_cornutum/

| The page says | The source says |
| :--- | :--- |
| turns its own eyes into blood-squirting weapons against predators | These lizards can also squirt blood from their eyes, which they spray at predators. |
| Arid prairies, dunes, deserts and desert-basin edges | Texas horned lizards reside in arid or semi-arid regions with access to open ground and some scattered vegetative cover. These areas include a number of early successional habitats like prairies, dunes, and deserts. They also include the edge habitat of playas, which are flat desert basins |
| from the southern Great Plains and southwestern United States into northern Mexico | Texas horned lizards (Phrynosoma cornutum) are distributed across the United States and Mexico ... as far west as southeastern Arizona and New Mexico. Texas horned lizards are commonly found throughout Oklahoma and Texas (note: "Southern Great Plains" summarizes the account's Oklahoma/Texas/Kansas/southeast-Colorado range.) |
| Mainly harvester ants (Pogonomyrmex); ants were 69% of prey items in 351 stomachs, plus other insects | The diet of Texas horned lizards mainly consists of harvester ants (Pogonomyrmex rugosus); however, if the opportunity arises, they will consume other insects. Pianka and Parker (1975) examined the stomach contents of 351 Texas horned lizards. Here, ants made up 69.0% of prey items found in these stomachs. |
| Blood-squirting eye defense | These lizards can also squirt blood from their eyes, which they spray at predators. |
| a lizard is sexually mature once it measures at least 69 millimeters (2.7 inches) from snout to vent, females grow larger than males | Upon reaching sexual maturity, the snout-vent length of Texas horned lizards measures a minimum of 69 mm. Female Texas horned lizards are larger than the males. (note: 69 mm = 2.7 in. ADW's maximum lengths are not used: its prose gives females 144 mm and its table 69 to 114 mm, and neither says whether it is snout-vent or total length.) |
| body mass runs between 25 and 90 grams (0.9 to 3.2 ounces) | Their mass ranges from 25 to 90 g. (note: 0.88 and 3.17 oz (ADW's table) rounded to 0.9 and 3.2.) |
| round-bodied, spike-crowned lizard of the arid prairies, dunes and deserts | Texas horned lizards reside in arid or semi-arid regions with access to open ground and some scattered vegetative cover. These areas include a number of early successional habitats like prairies, dunes, and deserts. |
| running from southeastern Colorado and southwestern Missouri down through Oklahoma and Texas | Their range extends as far north as southeast Colorado, Kansas, and southwest Missouri. ... Texas horned lizards are commonly found throughout Oklahoma and Texas |
| into northern Mexico | They live as far south as the Mexican states of northeast Sonora, Chihuahua, Durango, Zacatecas, San Luis Potosí, and Tamaulipas. (note: "Northern Mexico" summarizes these named Mexican states.) |
| Two brow horns crown its head, more spikes run along its jaw, and two rows of spines line its flanks | The largest horns crown their heads: two form the brow, while more protrude from the jawline and up to the temporal portion of the skull. Two rows of spikes line the lateral portions of their torso |
| If a threat keeps coming, the lizard hisses and lunges, and it can also | If the threat approaches, they will hiss and lunge to defend themselves. These lizards can also squirt blood from their eyes, which they spray at predators. |
| raise the blood pressure inside its sinus orbitalis, a sinus in the eye socket, until a blood vessel ruptures and a passage opens into the conjunctival sac, so blood sprays out at the predator | They do this by forcing the blood pressure within the sinus orbitalis to increase, causing the blood vessel to rupture and forcing a passage to be formed into the conjunctival sac. (note: "A sinus in the eye socket" glosses orbitalis (of the orbit). "Until" paraphrases "causing".) |
| One individual studied by Burleson in 1942 squirted blood from its left eye across nearly a meter | An individual studied by Burleson (1942) ejected blood from its left eye at a distance of nearly 1 meter. |
| The lizard builds the pressure itself until the vessel gives way | forcing the blood pressure within the sinus orbitalis to increase, causing the blood vessel to rupture |
| then sprays the blood at predators | which they spray at predators. |
| When Pianka and Parker opened the stomachs of 351 of these lizards, 69.0% of the prey items were ants | Pianka and Parker (1975) examined the stomach contents of 351 Texas horned lizards. Here, ants made up 69.0% of prey items found in these stomachs. |
| A single lizard can take from about 30 to more than 100 ants a day | A single Texas horned lizard can consume from about 30 to over 100 ants per day. |
| waiting at a colony entrance, tilting its head sideways and down, and lapping them up with a sticky tongue | Texas horned lizards have been observed waiting at colony entrances of harvester ants between the hours of 0900-1100 h ... To catch their prey, Texas horned lizards tilt their heads sideways and downwards, then quickly lap them up into their mouths with their sticky tongues. |
| Its horns are thought to be a defense: they have been found puncturing the throats of canids (the dog family), rattlesnakes, whipsnakes, falcons and hawks that preyed on it | It is thought that the horns of horned lizards are used to defend against predators. The horn of this species have been found puncturing the throats of all listed species except greater roadrunners. (note: ADW's Known Predators list: Canids, western diamondback rattlesnake, sidewinder, Sonoran whipsnake, coachwhip, prairie falcon, American kestrel, loggerhead shrike, red-shouldered hawk, greater roadrunner.) |
| The greater roadrunner is the listed exception: it crushes the lizard's skeleton against a rock, then eats it head first | Greater roadrunners kill Texas horned lizards by crushing their skeletons against a rock, then consuming the lizard head first, a method of consumption which has allowed them to avoid the same fate. |
| it has declined throughout central Oklahoma and Texas since the 1960s | Since the 1960s, they have declined throughout central Oklahoma and Texas. |
| Within Texas, though, urban growth over its habitat, collection as pets and pesticides reducing the harvester ants it eats have all contributed to its decline | the urbanization of their habitat, collection as pets, and the loss of their main food source have all contributed to their decline. Harvester ants (Pogonomyrmex rugosus) make up 69% of their diet, but they are facing a decline due to the use of pesticides. |
| Nearly a meter: one lizard studied in 1942 shot blood that far from its left eye | An individual studied by Burleson (1942) ejected blood from its left eye at a distance of nearly 1 meter. |
| It raises the blood pressure in a sinus in its eye socket until a blood vessel bursts, and the blood is forced into the pocket between eyelid and eyeball | They do this by forcing the blood pressure within the sinus orbitalis to increase, causing the blood vessel to rupture and forcing a passage to be formed into the conjunctival sac. (note: "The pocket between eyelid and eyeball" glosses the conjunctival sac.) |
| Mostly harvester ants, plus other insects when the chance comes | The diet of Texas horned lizards mainly consists of harvester ants (Pogonomyrmex rugosus); however, if the opportunity arises, they will consume other insects. |
| Ants were 69% of the prey items researchers counted in the stomachs of 351 lizards | Pianka and Parker (1975) examined the stomach contents of 351 Texas horned lizards. Here, ants made up 69.0% of prey items found in these stomachs. |
| one lizard eats roughly 30 to over 100 ants a day | A single Texas horned lizard can consume from about 30 to over 100 ants per day. |
| Low | The only harm Texas horned lizards can do to humans is bite. While normally a docile species, Texas horned lizards may lunge at a human if threatened. |
| it can inflate itself with air so the spikes stand out, making it harder for a predator to eat | They can also inflate themselves full of air so their spikes protrude, making them more difficult for predators to consume. |
| Its diet is mainly harvester ants | The diet of Texas horned lizards mainly consists of harvester ants (Pogonomyrmex rugosus) |
| tags: camouflage | Depending upon the geographic region, Texas horned lizards will have coloration that resembles the color of the ground. (note: Settles #732: ground-matching coloration by region fits the tag definition (coloration that blends the animal into surrounding terrain).) |
| it forces up the blood pressure behind its eye until a vessel ruptures and blood sprays nearly a meter at the predator | An individual studied by Burleson (1942) ejected blood from its left eye at a distance of nearly 1 meter. They do this by forcing the blood pressure within the sinus orbitalis to increase, causing the blood vessel to rupture (note: vibe.reason, settled in #732 (was geography and mood).) |

## Hammerson (2007). Phrynosoma cornutum. The IUCN Red List of Threatened Species 2007: e.T64072A12741535.

https://doi.org/10.2305/iucn.uk.2007.rlts.t64072a12741535.en

| The page says | The source says |
| :--- | :--- |
| Least Concern | IUCN Red List category: Least Concern (LC). (note: Category checked through GBIF's copy of the Red List, as iucnredlist.org refuses scripts; the assessment DOI is the cited reference.) |
| The IUCN Red List rates the Texas horned lizard Least Concern | IUCN Red List category: Least Concern (LC). |
| The IUCN Red List rates it Least Concern | IUCN Red List category: Least Concern (LC). |

## Comanns et al. (2011). Moisture harvesting and water transport through specialized micro-structures on the integument of lizards. Beilstein Journal of Nanotechnology.

https://doi.org/10.3762/bjnano.2.24

| The page says | The source says |
| :--- | :--- |
| A honeycomb-shaped microstructure on its scales makes the skin superhydrophilic | the honeycomb like structures render the surface superhydrophilic, most likely by holding a water film physically stable |
| a droplet spreads almost instantly and soaks into a network of capillary channels running between the scales | an almost immediate spreading of the droplet on the moisture harvesting animals, i.e., Moloch horridus, Phrynocephalus arabicus and Phrynosoma cornutum can be seen |
| those channels are wired to favor one direction | the velocity towards the mouth, i.e., rostral is significantly higher than for all other directions |
| in lab tests, water moving toward the mouth flowed at about 3.15 millimeters a second, against roughly 1.6 to 1.8 millimeters a second sideways or toward the tail | P.c. 3.15 ± 0.94 / 1.84 ± 0.24 / 1.61 ± 0.45 (note: Table 1's average water transport velocity (mm/s) for Phrynosoma cornutum (P.c.): rostral / lateral / caudal, measured in the first 333 ms after applying water.) |
| Its scales carry a microscopic honeycomb texture that makes water spread across them rather than bead | All three lizards have a honeycomb like micro ornamentation on the outer surface of the scales (note: "Spread rather than bead" glosses superhydrophilic (claim 24).) |
| tiny channels between the scales then move that water toward its mouth faster than in any other direction | the velocity towards the mouth, i.e., rostral is significantly higher than for all other directions (note: "Faster" paraphrases the source's "significantly higher" velocity; same comparison (mouthward vs. every other direction).) |

## Comanns et al. (2015). Directional, passive liquid transport: the Texas horned lizard as a model for a biomimetic 'liquid diode'. Journal of The Royal Society Interface.

https://doi.org/10.1098/rsif.2015.0415

| The page says | The source says |
| :--- | :--- |
| skin channels that steer water toward its snout | their skin is capable of collecting and transporting water directionally by means of a capillary system between the scales. This fluid transport is passive ... and directs water preferentially towards the lizard's snout. |
| No muscles or pumping are involved, just channels that narrow and widen along the way | This fluid transport is passive, i.e. requires no external energy ... based on geometric principles, namely on a periodic pattern of interconnected half-open capillary channels that narrow and widen. |
| Its skin also collects water from sources such as moist sand and dew | Special skin adaptations enable them to access water sources such as moist sand and dew |

## Sherbrooke & Kimball (2024). Antipredator Blood-Squirting Defense in Horned Lizards (Phrynosoma): Chemical Isolation of Plasma Component(s), Pogonomyrmex Ant Dietary Origin, and Evolution. Ichthyology & Herpetology.

https://doi.org/10.1643/h2021139

| The page says | The source says |
| :--- | :--- |
| tags: toxic-chemical | squirt systemic blood from circumocular sinuses during encounters with certain mammalian predators. The predators react with distinct revulsion. (note: Settles #732: the aversive plasma compound comes from its Pogonomyrmex ant diet (same abstract: "Plasma fractions from individuals of P. cornutum, a blood-squirting species, fed Pogonomyrmex had more aversive levels of the active compound(s) compared to those given a cricket diet").) |

## Lara-Reséndiz et al. (2015). Thermoregulation of two sympatric species of horned lizards in the Chihuahuan Desert and their local extinction risk. Journal of Thermal Biology.

https://doi.org/10.1016/j.jtherbio.2014.11.010

| The page says | The source says |
| :--- | :--- |
| A 2015 study measured its body temperatures at three Chihuahuan Desert sites in Mexico and fed them into an extinction model: if air temperatures rise as climate models predict, it projected local extinction at 6% of sites within the species' current range by 2050 and 18% by 2080 | at three contrasting Chihuahuan Desert sites in Mexico. Using these physiological data, we estimate local extinction risk under predicted climate change within their current geographical distribution. ... if air temperature rises as predicted by climate models, the extinction model projects that P. cornutum will become locally extinct at 6% of sites by 2050 and 18% by 2080 (note: 2015 is the paper's publication year (Journal of Thermal Biology, 2015). "Projected" keeps the model's hedge.) |