NARRATOR：

Listen to part of a lecture in a biology class.

FEMALE PROFESSOR：

For today's discussion, we'll review the case study on how some animals have behaviorally adapted to their environments.

Now you had to read about two animal species,:the Eastern marmot and the Olympic marmot.

Marmots are rodents... they're large ground squirrels about the size of an average house cat, and they live in a variety of habitats.

And even though they spend the significant portion of the year hibernating, according to this case study, marmots are still considered excellent subjects for animal behavioral studies. Why is that?

MALE STUDENT：

Well, when they're not hibernating, you can find them in open areas, and they're pretty active during the day, which makes them easy to observe, right? [rising tone]

FEMALE PROFESSOR：

[encouraging tone] Unh huh. So, first let's discuss the eastern marmots.

They reside throughout the eastern region of North America where there's a temperate climate, where the growing season lasts for at least five months of the year... which is when they do all their mating, playing, and eating.

MALE STUDENT：

Oh, I see... at first, I wasn't sure what 'growing season' meant just from the reading, but now I get it.

It's the amount of time it takes for them to grow, right? [rising tone]

So it would be five months?

FEMALE PROFESSOR：

Hm? Ohh, I'm sorry but no, It has nothing to do with that.

It's not about the time it takes for Eastern marmots to grow,It's when the food is available.

That is--when it’s not covered in snow and there's no frost covering the grass, and um vegetative parts of uh, plants, herbs, and the flowers that marmots like to eat.

So, 'growing season' refers to the availability of the food they eat. Ok?

So now how would you describe the Eastern marmots'social habits?

FEMALE STUDENT：

Well, they are really territorial, and loners, and just so aggressive even with other Eastern marmots.

And their mating ritual is just so... impersonal.

FEMALE PROFESSOR：

[agreement] Uh huh.

Now when they emerge in the spring from hibernation, the mating process begins.

For them, well, they come together to mate and then they go their separate ways.

Then about six to eight weeks after birth, the offspring leave their mothers.

FEMALE STUDENT：

Really? Just six weeks?

Is it possible for the offspring to make it on their own so young? [concerned]

FEMALE PROFESSOR：

Well, it's not as if they aren't ready for the real world because they are.

Remember, they mature quickly and the weather's nice.

Also they live in open fields where there is lots of edible vegetation.

So roughly six weeks after birth, eastern marmots are just old enough to take their chances of surviving in a temperate environment. [pause]

So how does this relate to their behavior?

FEMALE STUDENT：

Oh, I get it.

Since the climate's not too bad, the Eastern marmots don't have to rely on each other too much and they really don't need to stay together as a family to survive either.

FEMALE PROFESSOR：

Uh huh. And in contrast... the Olympic marmots... what about them?

FEMALE STUDENT：

Well, they live together as a family and take care of their young until they are at least two years old.

They're really friendly with each other, and what I really like is that they even have greeting ceremonies and they're not at all aggressive and territorial like the eastern marmots.

So their social behavior is so different from Eastern marmots because of the climate where they live?

That seems so bizarre.

FEMALE PROFESSOR：

Well, the Olympic marmots inhabit meadows high in the Olympic Mountains where the weather conditions are much harsher so there is a lot more wind and snow.

The growing season only lasts about two to three months.

So in that much shorter period of time, all the Olympic marmots, male and female, eat, play, work and nurture the young together.

Because the climate is so harsh, cooperation increases the survival rate of the Olympic marmots.

They keep their young at home until they are physically able to survive on their own.

This could explain why the social behavior of the Olympic marmots is so unlike that of the Eastern marmots.