The 423 parks in the National Park System offer visitors a chance to see landscapes and animals in their natural state — or as close to it as most of us are likely to see.
Researchers tracked how often moose, wolves, black bears, and brown bears appeared on the cameras. With no humans around, brown bears and moose appeared up to eight times per week, black bears up to six times, and wolves up to four times.
The researchers acknowledge animals at more popular parks may be less shy of humans than those at Glacier Bay. For smaller parks, though, an increase in visitors could drastically change animal behavior.