AnAge entry for Ursus americanus

Classification (HAGRID: 02251)

Taxonomy: Kingdom: Animalia
    Phylum: Chordata
        Class: Mammalia (Taxon entry)
            Order: Carnivora
                Family: Ursidae
                    Genus: Ursus
Species: Ursus americanus
Common name: American black bear

Maximum longevity: 34 years (captivity)
Source: ref. 671
Sample size: Large
Data quality: Acceptable
Observations: During hibernation body temperature floats around 32.5 degrees C. Although pregnancy in bears lasts for about 220 days, there is a delayed implantation and embryonic development only occurs in the last 10 weeks of pregnancy [0434]. In the wild, it has been suggested that they may live over 33 years [0558], which is dubious. Record longevity in captivity belongs to a wild born female that was about 34 years when she died in captivity [0671].

No information on metabolism is available.

[0671] Richard Weigl (2005), Longevity of Mammals in Captivity; from the Living Collections of the World
[0559] Freedman et al. (2003), Life history analysis for black bears (Ursus americanus) in a changing demographic landscape
[0610] Ernest (2003), Life history characteristics of placental non-volant mammals
[0434] Ronald Nowak (1999), Walker's Mammals of the World
[0079] Uchida et al. (1995), Senile plaques and other senile changes in the brain of an aged American black bear (PubMed)
[0676] Purvis and Harvey (1995), Mammal life-history evolution: a comparative test of Charnov's model
[0455] Virginia Hayssen et al. (1993), Asdell's Patterns of Mammalian Reproduction: A Compendium of Species-Specific Data
[0955] Cork et al. (1988), Neurofibrillary tangles and senile plaques in aged bears (PubMed)
[0680] Wootton (1987), The effects of body mass, phylogeny, habitat, and trophic level on mammalian age at first reproduction
[0731] Zullinger et al. (1984), Fitting sigmoid equations to mammalian growth curves
[0558] North American Bear Center