At this time of year, bears are more likely to become aggressive due to the urgency of fattening up for winter.

The overall wildebeest population has seen a sharp decline in recent years, falling below 600,000 animals.

The researchers selected human words not already familiar to the whale to see if it could mimic new sounds.

In the fall cleaning campaign, Yellowstone's geology team discovered a trove of unusual items tossed by visitors.