Picture trying to survive in eucalyptus forests in eastern Australia. For many animals, a habitat like this would be impossible. Yet the koala, a mammal about 75 centimeters long, thrives there, thanks to features that scientists call adaptations: traits that help a living thing survive in its environment.
Consider sharp claws and rough pads on its paws: this adaptation help it grip smooth tree trunks. Equally important is a very long gut, which helps it break down tough, poisonous eucalyptus leaves. Without these traits, the koala would struggle to last a single season.
As a herbivore, the koala is an animal that eats only plants; it depends on eucalyptus leaves. Its behavior matters as much as its body: it sleeps up to 20 hours a day in the forks of trees. Behaviors like this are adaptations too, even though you cannot see them in a photograph.
The next generation faces the same challenges. Young koalas, called joeys, depend on their surroundings and on adult care. A newborn joey is the size of a jelly bean and grows inside its mother's pouch for about six months.
Perhaps most remarkable of all: koalas get most of the water they need from the leaves they eat. Facts like this remind us that every animal's body tells a story about the place it lives.