The frilled lizard often avoids fighting by flaring the large frill around its head, using surprise to discourage a threat before it turns into a chase or a bite. These lizards live in northern Australia and southern New Guinea, spending most of their time clinging vertically to tree trunks. Their bodies are lightweight and built for short bursts of speed and climbing, not for brawling. In the wild, even a small injury can be hard to recover from, so their best strategy is to avoid danger in the first place.
Most of the time, the frill lies flat against the neck. It’s only when something gets too close that the lizard reacts. As it rears up and opens its mouth, the frill springs open at the same time. The frill is supported by cartilage and controlled by muscles linked to the jaw, so opening the mouth and flaring the frill happen together in one quick motion.
Why the display works so well
When the frill opens, several things happen at once. The lizard suddenly looks bigger. The wide, circular shape breaks up its body outline, making it harder for a predator to judge size or distance. At the same time, the open mouth reveals flashes of bright color, often yellow or orange, and the lizard might hiss or make a quick snapping sound.
All of this creates a brief moment of confusion. A predator that was about to strike might pause just long enough for the lizard to escape. That hesitation is what the lizard is counting on. The goal isn’t to scare the predator for long, but to disrupt the decision to attack.
What the lizard does if the display fails
If the predator keeps coming, the lizard doesn’t stand its ground. It instantly shifts to escape mode. It drops forward and bolts, often sprinting on its hind legs for a short distance. Running upright gives it better speed and balance across uneven ground. The goal isn’t to run far, but to reach the nearest tree.
Once there, it climbs fast and presses itself flat against the trunk. Its coloring and stillness help it blend in, and the frill is already tucked away. The moment has passed, and in most cases, that’s the end of the encounter.
Behavior breakdown
To see how this works so reliably, here’s a simplified breakdown of the sequence:
The remainder of this post is for members only.
Becoming a member supports our independent reporting.
Members get full access to in-depth animal behavior coverage across species, complete stories, and the full archive.
