Mortality and morbidity

Abstract

Like any wild mammal, beavers face a range of mortality risks including direct predation and infectious diseases. Their main predators are the wolf and bears. Beavers are also predated by alligators, coyotes, wolverines, cougars, lynx, bobcats, dogs, and foxes. Territorial fighting can have an indirect impact on beaver survival leading to injury and infection. Human-mitigated factors such as pollutants, hunting and trapping, and less documented causes of deaths such as road traffic and motorboat accidents, drowning, water regulations, floods, dental issues, harsh winters, droughts, tree felling are also discussed. This chapter discusses a range of pathogens that may be harboured by beavers and diseases caused by viruses (three rare ones in the North American beaver), bacteria (18), and internal (49) and external (65) parasites specific to beavers. The most common bacteria is the Tularemia and it occurs most often in the North American beaver. The most common endoparasites are the Giardia spp. (occurs mostly in the North American beaver), the roundworm Travassosius spp. and the beaver fluke. The most common ectoparasites are the beaver parasite beetle, and mites in the genus Schizocarpus spp.