The unique appearance of horned lizards, with their spiky protrusions, has fascinated people for centuries. But those horns serve an important purpose – defense. If you’re short on time, here’s the quick answer: Horned lizards use their horns to make themselves appear larger and more intimidating to predators.
The horns also make the lizards harder to swallow. This article will provide a deep dive into the various defensive abilities of horned lizards.
In this comprehensive guide, we’ll explore how horned lizards rely on their horns and other adaptations to avoid becoming prey. We’ll learn about their arsenal of defenses, from camouflage to blood-squirting, and explain why the horns help make them so effective at surviving attacks from potential predators.
Physical Adaptations
Horns
The horns of horned lizards are one of their key physical adaptations for defense (animaldiversity.org). Protruding from their heads and upper bodies, the horns make the reptiles appear much more formidable to potential predators.
When threatened, horned lizards can flex the horns to seem even larger, serving as an effective deterrent.
In some horned lizard species like the Texas horned lizard, the horns contain tiny pores that secrete blood-like droplets. This unique red liquid contains foul-tasting chemicals that repel predators trying to eat them.
So the horns act as nozzles to spray out the repellent fluid when the lizards are attacked.
Spines and Scales
The horned lizard’s spiny scales and body armor provide an additional defense mechanism by making them difficult and painful to swallow. Their specialized scales have sharp tips pointing backwards (desertmuseum.org). This deflects strikes from predators like birds of prey and coyotes.
Some types like the coastal horned lizard even flatten their bodies and spread their sharp spines when under attack. This increases their width and makes them harder to grasp and consume.
Camouflage
Horned lizards rely on camouflage to avoid detection from predators. Their colors and patterns act as natural disguises blending into the desert environment. For example, the regal horned lizard’s back can change from shades of grey to reddish brown depending on light conditions and temperature (gilbertparks.com).
When motionless, it’s very difficult for predators to notice them. Some species can even deliberately darken their skin color to match the substrate they are on. So camouflage works very effectively as the first line of defense.
Defensive Behaviors
Inflating the Body
When threatened, horned lizards can inflate their bodies to appear larger and more intimidating to predators. They suck air into specialized pouches in their bodies, increasing their size by up to 50%!This makes it more difficult for a predator to swallow them. The sharp horns and spiky scales also deter predators when the lizard is inflated.
Biting
If inflating their bodies does not scare off the threat, horned lizards will bite predators. Their powerful jaws and sharp teeth can deliver a strong and painful bite. Although not venomous, the bite serves as an effective defense mechanism against small predators.
Playing Dead
An ingenious trick horned lizards use is playing dead. When grabbed by a predator, they go limp and appear lifeless, even letting their tongues hang out of their mouths! This often startles the predator into dropping or releasing them.
According to the Arizona-Sonora Desert Museum, they can maintain their death-feigning act for up to an hour.
Squirting Blood
The most shocking defense mechanism horned lizards employ is squirting streams of blood from their eyes! Amazingly, they can shoot blood up to 5 feet. This is made possible by specialized sinus regions around their eyes.
When threatened, they restrict blood flow leaving the head, resulting in a dangerous increase in blood pressure. Veins around the eyelids then rupture, squirting attacker with blood. This bizarre behavior likely confuses predators long enough for the lizard to flee.
Predator-Prey Relationships
Common Predators
Horned lizards have many natural predators due to their small size and inability to move quickly over long distances. Common predators include birds of prey like hawks and falcons, as well as coyotes, foxes, snakes, and even house cats.
In some areas, the most dangerous predators are invasive species like fire ants, which attack hatchlings before their horns have fully formed.
Avoiding Capture
Horned lizards have evolved clever ways to avoid becoming prey. Their camouflage allows them to blend in with their rocky surroundings, and their ability to flatten their bodies against the ground helps them hide in plain sight.
When threatened, they rely on their speed and agility to scurry away to safety, darting between rocks and vegetation. Some species may also squirt blood from their eyes to startle predators!
Surviving Attacks
If caught by a predator, horned lizards have a few tricks up their sleeves to survive. Their spiny body makes them difficult to swallow, and as a last resort, they can detach their tail to escape a predator’s grasp.
Their unique defense mechanism against invasive fire ants is especially fascinating – they can squirt streams of blood from pockets near their eyes, which contains a chemical that tastes awful to the ants. This blood-shooting ability allows many horned lizards to survive fire ant encounters.
Though small, horned lizards are mighty lizards with impressive survival skills!
Conclusion
The myriad adaptations of horned lizards, from their namesake horns to their ability to squirt blood, make them difficult prey for would-be predators. Their impressive defenses allow them to hold their own against a variety of animals that would otherwise eat them.
While no single tactic provides complete protection, the combination makes horned lizards a formidable foe.
The next time you see a horned lizard in the wild, take a moment to appreciate the many fascinating ways it has evolved to detect and deter potential predators. Its spines and scales, camouflage, odd behaviors, and capacity to shoot blood from its eyes all contribute to its survival, ensuring that the horned lizard continues to thrive despite the many animals that would love to make a meal of it.
