A wood frog nestles under frozen leaves 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. The animal dies. A wood frog’s body produces a high level of sugar in its blood. It acts as an antifreeze. It protects the frog by not allowing ice to form inside the cells. In spring, the frog thaws out.

Lying in the desert sand, the Texas horned lizard is motionless. It looks like a spiky rock.

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

The coyote is not impressed. It pounces and pins the lizard to the ground. The lizard launches its extreme defense. As the coyote comes in to bite it, the lizard squeezes blood from its eyes. It squirts it into the coyote’s mouth. Yuck!

The blood tastes disgusting. As the coyote backs off, the lizard runs away!

Some animals use surprising hunting strategies. Others find ways to live in unsafe environments or avoid being eaten. All of these animals rely on extreme adaptations for every‑day survival.