Grand Teton moose have learned a lot since then. Most of us think of moose as these dim lumbering Bullwinkles, but they figure things out. Today, if I were to play wolf calls over a loudspeaker to a herd in the park, they’d become vigilant  and they’d move away.

Image 'We think that the Grand Teton moose have figured out a way to use humans as shields for their babies.' - Joel Berger. Credit... Tom Bauer for The New York Times

Q. Isn’t this just moose instinct at work?

A. No. They didn’t do it 15 years ago.

Q. Why did you once dress up as a moose?

A. Legitimate scientific inquiry. We wanted to see how the Grand Teton moose reacted to the smell of bear scat. In Alaska, where the moose are very bear-savvy, if they smell it, they’ll manifest fear. But what about “naïve” moose? Well, you can’t just go up to moose and put odiferous bear poop patties before them. The outfit  and a tactic of acting like a moose  was a way of getting in close. We only did this perhaps four times, but I’ll never live it down. The media made a big deal of it. Letterman wanted me on his show. We didn’t go.

Q. How did your guys react to the bear patties?

A. At that time, bears hadn’t been that much of a danger to them. And so they mostly ignored it. But within one moose generation, really only a few years, they started to wise up.

Q. We found a book by you, “Bison: Mating and Conservation in Small Populations.” Are you the Alfred Kinsey of the bison world?

A. This was serious work, again. Our team spent over 9,000 hours over a five-year period watching bison copulations that lasted for less than 10 seconds each.

Bison in the Badlands park in South Dakota, where we were working at that time, are genetically as if on an island. They are surrounded by a sea of human domination, and no new ones are going to migrate in. Thus, the potential for inbreeding is high. We wanted to observe mating patterns to see if it would work to bring in outside males to diversify the gene pool. The question was, Would these introduced males be allowed to mate with the females.