NARRATOR：

Listen to part of a lecture in a biology class.

FEMALE PROFESSOR：

Okay, so many animals benefit from living in groups ...

it provides them with protection from predators and, uh, with social companionship...

So it’s important for these animals to maintain their group’s unity.

They need ways to either avoid conflicts, or, if they do occur, to resolve them peacefully.

To help them achieve this, many animals use what are called display behaviors.

These are behaviors that are mostly for show ...

uh, symbolic behaviors that send a message to the other animals and help maintain their group’s unity.

One way is through the use of threatening display behaviors.

Threatening display behaviors are used to communicate a warning, but they aren’t meant to really harm other animals.

Rather, they help animals avoid fights.

Some monkeys—like baboons, for instance—frequently use threatening display behaviors.

Like... well, let’s say two baboons find some fruit and they both want it.

One baboon—maybe the first baboon to see the fruit—might stare at the other one ...

and make threatening noises—grunts—to let the other baboon know it wants the fruit.

Because the other baboon understands the meaning of the stares and grunts, it can give up the fruit without a fight.

And this behavior benefits the group ... by preventing conflict.

But sometimes physical fights do occur ...

and animals need a way to reconcile afterwards, to make up ...

to ensure that everyone in the group continues to get along.

In these cases, an animal might use friendly display behavior to restore group unity.

Uh... let’s return to the baboon example.

Let’s say the two baboons do end up getting into a physical fight over the fruit.

After the conflict, the two animals need a way to resolve things.

So what they do is approach each other while making friendly noises, and may even hug each other...

as if to say, “Everything’s okay now. I’m not angry with you anymore.”

Through this display behavior—friendly noises or hugs—the baboons can make up and the group can go back to normal.