Horned Lizard
Weirdness 9/10

The lizard that shoots blood out of its own eyes

When this lizard is cornered, it shoots a jet of its own blood straight out of its eyes.

📋 Fact File
🐾 Reptile🍽️ Insectivore
📏 Size
About 7-13 cm (2.5-5 in) long
Small enough to sit in the palm of your hand
Lifespan
About 5-8 years in the wild
🟢 Least ConcernIt's still common overall, but it's disappearing in some areas as its ant food vanishes.
🤔 Guess first

Which one is REALLY true about the Horned Lizard?

The short version

ages 9–12

The horned lizard restricts blood flow from its head until vessels around its eyes burst, firing a jet of foul-tasting blood up to five feet to repel coyotes and foxes. It also uses camouflage, a crown of sharp horns, and can puff up to look too big and spiky to swallow.

📏 How big is it, really?
Horned Lizard
13 cm
Horned Lizard
a 7-year-old
1.2 m
🧒

You could line up about 9 of them along a 7-year-old!

Why it's so weird

  • The Horned Lizard shoots a jet of its own blood up to five feet straight out of its eyes when cornered.
  • The Horned Lizard restricts the blood flow leaving its head until the pressure bursts tiny vessels around its eyes.
  • The Horned Lizard fires blood that tastes absolutely foul to dogs and cats, making attackers drop it and run.
  • The Horned Lizard relies on and a crown of sharp horns to avoid ever being seen in the first place.
  • The Horned Lizard can puff its body up with air to look twice as big and far too spiky to swallow.

The full story

When this little lizard gets truly cornered, it shoots a stream of its own blood straight out of its eyes. Meet the horned lizard, a spiky desert reptile with one of the most bizarre defenses on the entire planet. First it relies on camouflage and its crown of sharp horns to avoid ever being seen. But if a predator like a coyote or a fox grabs it anyway, it pulls off its secret weapon. It restricts the blood flow leaving its head until the pressure bursts tiny vessels around its eyes, firing a jet of blood up to five feet away. That blood also tastes absolutely foul to dogs and cats, so the startled attacker drops it and runs. On top of all that, it can puff its body up with air to look twice as big and far too spiky to swallow. Follow for more weird animal facts.

🔬 The science — how & why

A horned lizard has tiny muscles that can squeeze shut the big veins that carry blood OUT of its head. When it clamps those veins, blood keeps flowing IN but can't drain away, so it pools in spaces around the eyes and the pressure shoots up, like pinching a garden hose. That rising pressure swells until it bursts the thinnest, weakest blood vessels near the eyelids, firing out a jet of blood. The blood tastes terrible to dogs, coyotes, and foxes, and scientists think this is linked to the venomous harvester ants the lizard eats.

📚 Source: AskNature: Eyes Squirt Blood (Biomimicry Institute)
🔎 How do we know?

Scientists saw it happen in real predator tests: in studies by Middendorf and Sherbrooke, captive coyotes that attacked Texas horned lizards got squirted and reacted by jerking back, shaking their heads, and wiping their mouths, and later tests showed the bad taste works through receptors in the mouth and nose.

📚 Source: Antipredator Blood-Squirting Defense in Horned Lizards (USDA NWRC; Middendorf & Sherbrooke)
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The Horned Lizard shoots a jet of its own blood up to five feet straight out of its eyes when cornered.

The Horned Lizard has a heart that can beat over 1,200 times every minute.

The Horned Lizard restricts the blood flow leaving its head until the pressure bursts tiny vessels around its eyes.

🍎 Teacher or parent? Print a Horned Lizard research worksheet or open the lesson hub.

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Horned Lizard gallery

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