Yea,Timothy Treadwell studied grizzlies,he figured out they were smart enough to kill his crazy ass. Both animals are smart in their own right,but they tend to behave very differently because of the survival requirements in their regions of the world. The grizzly because of his tends to have to be a proficient killer because he has to eat alot before the harsh winters set in.
This basically amps up his predator mode into high gear,as the above stupid as hell Timothy Treadwell had learned. The grizzly is a born killer and kills for whatever reason,food,if attacked,whatever,the gorilla will kill if it has to if it is attacked or to get the females and become the head of its group,but it typically is a bluffer and does not kill for food as it is a vegetarian. The bear tends to not bluff,it tends to just kill and eat you if it feels like its worth the effort.