TODAY | May 27, 2013
>>> well, animals and "alf" are always trending online. as we try to plow forward, nothing meets the rare sight of a grizzly bear . yellowstone national park is one of the only areas south of canada where you can still encounter face to face grizzly bears . recently i threw caution to the wind, went out to the park in search with a little help of the elusive grizzly.
>> reporter: massive and powerful, the grizzly bear is one of the most feared animals the world over. an endangered species . one of the last refuges for grizzlies in the lower 48 states is here in the greater yellowstone area.
>> in almost all bear attacks, the bear is responding to a surprise encounter. it's reacting defensively.
>> reporter: male grizzlies can top the scales at over 700 pounds. they're surprisingly fast.
>> they're faster than olympic sprinters. they're faster than olympic sprinters on steroids.
>> reporter: i met up with casey anderson, fifth generation montana montanans. he leads tracking expeditions out into the remote montana wilderness. how you doing, man?
>> reporter: thanks for having me up here. what's the behavior of the bears? they're coming out of hibernation.
>> they've been literally not eating, drinking for five months. so now they've come out of the den, and now they're trying to make up all that lost weight. in order to be out there safely, i'm going to give you one of these. this bear spray essentially is your protection against a grizzly bear .
>> reporter: let's head out.
>> we're just now getting into the sweet spot . look at that, a moose track. a moose. that's a very good sign that there's a bear up there. one of the classic tracking rules is that if you want to know where the big animals are, listen to the little animals.
>> reporter: deeper into the wilderness, we made a breakthrough, fresh grizzly tracks.
>> definitely a grizzly track. super characteristic of a grizzly track is these giant claws that you see here. they can be four inches long.
>> reporter: what size bear is he?
>> he's about a 600-pound grizzly. yeah.
>> reporter: how fresh does that look to you?
>> well, i didn't see it yesterday. let's try to find this guy. there's at least two bears here right now. let's keep poking up the hill. there's a bear in there. about 600-pound big male. about as big as they get. i call him black bart because he's got that super dark coat.
>> reporter: the moment where he stopped, turned and looked at us --
>> he knew we were here. yep. two bears. two good-size grizzlies. could be a female with a male in hot pursuit. this shows how much activity in such a small area, which is pretty rare.
>> reporter: so by my count, three grizzlies, moose, coyotes, birds. that's a pretty good day. you told us if a grizzly bear gets up on hind legs, back away quietly.
>> reporter: i'm so glad i didn't have to test that advice. i appreciate you taking the time.
>> it was awesome.
>> reporter: it was a lot of fun.
>> what a cool experience.
>> my thanks again to casey anderson, such a cool guy, knew exactly where to set up shop and patiently look for a grizzly. good news, i did not have to use the bear spray . he said it's very rare that you ever have to use that.