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
Lifespan, ageing, and relevant traits
- 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].
Life history traits (averages)
- Female sexual maturity
- 1,278 days
- Male sexual maturity
- 1,278 days
- Gestation
- 70 days
- Weaning
- 198 days
- Litter size
- 2 (viviparous)
- Litters per year
- 0.4
- Inter-litter interval
- 730 days
- Weight at birth
- 277.5 g
- Weight at weaning
- 14,050 g
- Adult weight
- 154,250 g
- Postnatal growth rate
- 0.0029 days-1 (from Gompertz function)
- Maximum longevity residual
- 111%
Metabolism
No information on metabolism is available.
References
- [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
External Resources
- Integrated Taxonomic Information System
- ITIS 180544
- Animal Diversity Web
- ADW account (if available)
- Encyclopaedia of Life
- Search EOL
- NCBI Taxonomy
- Taxonomy ID 9643
- Entrez
- Search all databases
- Ageing Literature
- Search Google Scholar or Search PubMed
- Images
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- Internet
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