51 Clever Animals-High

Clever Animals FOCUS Question How do animals change their behavior in response to the environment?

Types of Traits Picture a black bear's sharp claws or its dark fur. These features of a bear's body are physical traits. Animals receive, or inherit, physical traits from their parents. Animals also have behavioral (be-HAYV-yur-ul) traits. These traits are how an animal acts. Behaviors can be inherited or learned. Bears sleeping all winter is an inherited trait. But cubs learn from their mother to scurry up trees when danger is near. Animals can change their behavior if something in their environment changes. A bear may eat seeds and berries in the summer. But it may eat insects in autumn when they are plentiful. Think About It Octopuses can unscrew the lid on a jar to get the food inside. Do you think they inherit or learn this behavior?

Stalking Behavior Animals can change how they hunt, depending on the environment. Leopards need to get close to their prey before they attack. They use different ways to do this. Savannas often have thick grass. Leopards will crawl quietly through the grass to stalk and catch prey. But in some places, there is no grass to hide in. In that case, a leopard may sneak down into a creek bed. It will follow the creek until it can pop up near its prey. Other times, a leopard will hide in a tree and wait until an animal walks below it. Then it pounces.

The Art of Attraction Many animals behave in specific ways to attract a mate. Male bowerbirds build impressive structures called bowers. First, they set up the basic framework. Then they decorate it with colorful items that they find in a forest or field. Different males use different colors. Cuttlefish can show off two color patterns on their skin at the same time. To find a mate, the male shows females the male color pattern on one side of its body. On the other side, it displays a female color pattern. This confuses other males trying to court the same female. It gives the first male time to attract a mate.

Bird Brains Birds can change their behavior to get a tasty treat. Some seabirds follow fishing boats. Shearwaters have learned that they can earn an easy meal by stealing some of what the people catch. When the boats don't go out, the birds hunt on their own. Seagulls have learned to drop crabs from great heights. The crab shell smashes open on the rocks below, and the seagull flies down to eat its meal. Crows have learned to do something similar with nuts. They drop the nuts on roadways. Then they wait for passing cars to run over them and break open the shells.

Wizards of the Waves Killer whales, or orcas, have several unique behaviors that help them catch their prey, which often includes other predators. No ocean creature may seem more dangerous than a great white shark. But a few kinds of orcas have figured out that by flipping great white sharks upside down in the water, they can turn these powerful fish into helpless prey. Great whites can only breathe while they swim. Once on their backs, the sharks stop swimming. They can suffocate in a few minutes. At that point, the orcas have landed quite a catch! Orcas in Argentina swim out of the surf and up onto dry, sandy beaches to catch sea lion pups. Orcas in Antarctica use a different trick. Weddell seals rest on large blocks of ice. By swimming as a group, the orcas create waves large enough to break the ice into smaller pieces. These waves wash the seal right off the ice, where it lands near the waiting jaws of another orca (see page 7).