The greatest risk to grizzlies is:
Disease
Low reproduction
Habitat loss

A grizzly bear home range will vary between:
27 to 1350 square km
10 to 100 square km
50 to 1000 square km

On average, a full-grown male grizzly is:
More than half a metre taller than the average person
About as tall as the average human
Smaller but much faster than a black bear