The rock squirrel; the most dangerous animal in Grand Canyon National Park. Rock squirrels commonly bite visitors who are feeding them, or who are just holding their finger out towards them. Park rangers regularly tell visitors that squirrels are the most dangerous animal in the park because squirrel bites are so frequent.

Squirrels that are fed by people become dependent on human food, and may lose their natural fear of humans and their ability to forage for natural foods. There is a lot of truth to the saying, “a fed animal is a dead animal.” In addition to losing their foraging ability, animals that have been fed are less likely to survive other reasons. Animals that have been fed from cars congregate near roadways and are at a high risk of being killed by vehicle collisions.

There are other serious hazards associated with wildlife. Numerous species, including rodents, squirrels, coyotes, fox, bats, and mountain lions, may carry infectious diseases such as Hantavirus, rabies, or plague. In some situations, these diseases may be transmitted through simple contact, such as touching or feeding wildlife. In recent years, Hantavirus, rabies and plague all have been documented in the park’s wildlife populations. NPS photo by Michael Quinn