Yellowstone National Park advises maintaining 25 yards distance from bull elks during mating season to prevent unprovoked attacks.

Yellowstone National Park urges visitors to stay at least 25 yards away from bull elks during their mating season, known as the rut, when elks become more unpredictable and aggressive. Safety measures include not approaching, using zoom lenses for photography, and finding shelter if needed. This warning comes as visitors are reminded not to provoke wildlife, especially during the mating season when incidents of unprovoked attacks can occur.