Name: 【TED-Ed】Tracking grizzly bears from space - David Laskin
Uploaded: 2015-01-24T02:34:01.000Z
Duration: 4 min 15 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

As you can see, they have big teeth and giant claws.

they're not as ferocious as you might think.

They play a critical role in the function of our ecosystems,

but, unfortunately, their habitat is dwindling fast.

Let's look at a threatened population of bears

Well, they're not for what you might think.

It turns out that grizzlies eat a lot of plants.

The ones that live here are almost vegetarians.

However, maintaining a diet of plants can be difficult.

In these northern latitudes, you have distinct seasons

where it's really nice and green for part of the year

If you eat plants, you have almost nothing to eat

So, you either have to migrate like geese

Their behaviors are closely synchronized with the seasons.

You need to be a highly effective forager.

So, bears tightly follow the schedule of the plants

at the point in time when they are at the most nutritious.

This will happen in different places at different times.

at the seasonal interaction between grizzlies and plants

to identify areas of the highest quality habitat.

Up here, two NASA satellites carry sensors

that are sensitive to the light reflected by vegetation.

that act like different chords on a piano

These signatures are recorded by the satellites every day

to see how they respond to the ebb and flow

Now, instead of ordinary, static habitat maps,

could be used for grizzly bear conservation

First, they help calculate the carrying capacity

where bears will be foraging at specific times.

by avoiding these areas during important feeding periods.

to predict the effects of climate change,

throwing the bears' precise foraging schedule out of whack.

Grizzlies are charismatic symbols of the wilderness.

These habitat maps made from satellite imagery