In a fascinating twist I certainly didn't expect, mother moose have been using the traffic around National Parks to shield their young from hungry grizzlies... In fact, the ten year study at Wyoming's Grand Teton National Park indicates that non-pregnant females tend to shy away from roadways, and that in areas without bears, even the pregnant ones stay away. Only pregnant or new mothers hang out near traffic until their young are old enough to run.
Apparently, the recent reintroduction of grizzlies to the area has led to the change in birthing behaviors. With some pregnant females giving birth as close as 50 yards from a major highway. But as time goes on, the expectation of the study's authors is that the bears will become increasingly bold, hunting for young calves right alongside the whizzing vehicles.Intriguingly, the study contrasts with a similar one done in Alaska's Denali National Park. But that study's author points out that it's most likely due to the long term association of people, bears, roads, and moose in Denali which leads both moose and bears to be largely indifferent to roadways there.
Both authors agree that we have previously underappreciated the degree to which the design of the infrastructure necessary to accomodate the millions of visitors to our National Parks has led to changes in the dynamics between predator and prey. Pointing out that's something we'll definitely need to take into greater account in the future.
via:: National Geographic