Not saying it is not set up but how would you go about that??

Find a mountain meadow. Take a crate full of Grizzly Bear and crate full of Cougar and let them both go in front of each other. Hope one does not kill the other. Let them scrap it out. Then re-capture said bear and cat who are all amped up after a good scrap.

As they say " that juice ain't worth the squeeze".

Probably just as difficult to locate that event in wild though...

There is one on there with a black bear fighting a cougar on an old Wild Kingdom. That looked like a set up but with classic commentary.