Reptiles of Big Bend

Shaka Guide


Introduction to the Chihuahuan Desert

Looking out this way to the west, you get a real sense of how vast this landscape is, you know? The arid Chihuahuan desert stretches nearly 250,000 square miles, nearly the size of Texas itself. And 90% of the desert is actually located in Mexico. This makes sense since the Mexican state of Chihuahua shares a border with West Texas.

Reptilian Diversity in Big Bend National Park

Curiously, the desert here is cooler and wetter than the Sonoran and Mojave deserts of the western United States, which is one reason it supports such a fantastic diversity of wildlife. And I'm not referring to the Mexican dog breed, the Chihuahua. What I'd like to talk about are reptiles.

Over 55 species of reptiles call Big Bend National Park home, including 31 species of snakes. And of course, that includes rattlesnakes. For the most part, rattlesnakes are shy and just as scared of you as you are of them.

One exception, though, is the western diamondback rattlesnake. I mean, western diamondback rattlesnake. These guys are known to be aggressive and are likely responsible for more snake bites than any other snake species in the United States. 

These venomous vipers are long, too. Adults can grow from four to six feet in length. Yeesh! That makes it the largest rattlesnake in North America. 

There are four species of rattlesnake in the park, but you can distinguish the western diamondback by looking for bands of black and white on its tail, just below the rattle. Also, like its name suggests, by looks for a diamond-shaped pattern on its back. Well, I don't mean to make you paranoid about snakes, so let me distract you by talking about another fascinating yet less threatening reptile in the park, the Texas-horned lizard.

Great name for a band, by the way. If you've not seen a horned lizard, I sure hope your luck changes today. These little guys are incredible. 

They're roughly five inches long, and fully grown, but what they lack in size they make up for in awesomeness. For starters, they're armored with spiny horns all around their body, and if they feel threatened, Texas horned lizards are capable of shooting, waiting for it, blood, waiting for it again, from their eyes. You heard me right. 

They'll shoot blood at a predator, which is, um, unexpected. But the lizard also mixes a little chemical in there so that their eye blood tastes god-awful. So with the predator totally baffled, the lizard makes its escape.

Marvels of the Texas Horned Lizard

And another thing, Texas horned lizards are capable of drinking water with their feet. I think I've heard it all now. And it's because of something called capillary action.

This happens when water flows upward against gravity through surface tension and adhesion to other surfaces. You know, like when you hold a towel and you let the bottom of it touch water? Even though the fabric is sort of standing upright, the water climbs as it's absorbed by the fabric. So when a horned lizard stands in a puddle, grooves in its skin direct water from its feet all the way to its mouth. 

Man, this guy was built to survive in this harsh environment. Do wonders never cease here? Perhaps it's these cool adaptations that made the Texas horned lizard the state reptile of Texas. Unfortunately, they're losing ground to habitat loss, and the pet trade is reducing their numbers in the wild. 

But here in the state of Texas, horned lizards are protected as a threatened species. That means possessing, handling, or even just touching one is illegal and subject to a fine. So let's let these awesome critters be and enjoy them from a safe distance. 

No, more than that. Step back more. No, you went too far. 

Two inches forward. What? Five centimeters? There you go. Perfect. 

After all, who wants to be on the receiving end of their repulsive eye blood, right? No, thank you very much.

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