A wood frog nestles under frozen leaves and grass in Alaska. Winter is coming. The temperature drops. The frog’s heartbeat slows. It takes its last breath and freezes solid. But it’s not dead! North American wood frogs simply take extreme measures to survive.

Most animals die when they get too cold. If ice forms inside their cells, the cells burst, and the animal dies. But a wood frog’s body produces a high level of sugar in its blood. The sugar acts as an antifreeze. It protects the frog by not allowing ice to form inside the cells. The rest of the frog’s bodily fluids turn to ice in the spaces between the cells. When spring arrives, the frog thaws. Its heartbeat and breathing return. The frog is as good as new!

Lying in the desert sand like a spiky rock, the Texas horned lizard is motionless. This lizard is a favorite food of lots of hungry desert creatures. Over time, it has developed some extreme adaptations to survive.

A nearby coyote lifts its nose and smells the air. It turns and spots the lizard. So much for camouflage! As the coyote approaches, the lizard hisses and puffs up to look bigger.

The coyote is unimpressed. It pounces and pins the lizard to the ground. Then the lizard launches its extreme defense. As the coyote comes in to bite it, the lizard straightens up. It squirts a stream of nasty-tasting blood from its eyes into the coyote’s mouth. This defense has adapted especially to deter attacking coyotes.

Here’s how it works: A pocket behind the lizard’s eyes fills with blood. The lizard squeezes the pouch and squirts the blood. The blood tastes disgusting to coyotes. As the coyote recoils, the lizard escapes.

Whether they are using surprising hunting strategies, finding ways to live in unsafe environments, or avoiding being eaten, some animals rely on extreme adaptations to survive.