Mexican grizzly bear

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Mexican grizzly bear
Mexican grizzly bear.jpeg
Diorama featuring Mexican grizzlies at the Field Museum of Natural History in Chicago, Illinois, USA

Extinct  (1964) (IUCN 2.3)
Scientific classification
  • Ursus horribilis nelsoni
  • Ursus nelsoni

The Mexican grizzly bear (Ursus arctos horribilis; formerly Ursus arctos nelsoni) is an extinct population of the grizzly bear in Mexico.

The holotype was shot by H. A. Cluff at Colonia Garcia, Chihuahua in 1899.[1] The extinct California grizzly bear extended slightly south into Baja California. The bears in Durango, Chihuahua, Sonora and central Mexico were likely more related to the bears of Arizona, New Mexico and Texas than to those of California.


Known in the Opatas language as the pissini,[2] the grizzly was one of the heaviest and largest mammals in Mexico. It reached a length up to 1.82 m (6 ft 0 in) and an average weight of 318 kilograms (701 lb).[3] Due to its silver fur, it was often named in Spanish as el oso plateado (the silvery bear).[4] The Mexican grizzly was smaller than the grizzlies in the United States and Canada. The general color was pale buffy yellow[5] varying to grayish-white, grizzled from the darker color of the underfur. Specimens in worn pelage varied to yellowish-brown and reddish.[2] The longest fur hairs were on the throat and the flanks. The belly was sparsely haired, lacking the thick underfur of the back and the flanks.[1]

Range and habitat[edit]

The bear inhabited the northern territories of Mexico, in particular the temperate grasslands and mountainous pine forests. Its previous range reached from across Aridoamerica, from Arizona to New Mexico, Texas and Mexico. It seems unlikely that the bears would have hibernated although they may have spent some time in winter dens.[6]


Like all brown bears, Mexican grizzlies were omnivores. Their diet mainly consisted of plants, fruits and insects, and it is reported that it was very fond of ants, like most brown bears.[7][8] Occasionally it fed also on small mammals and carrion. Females produced one to three cubs every three years or so.[7]


The first Europeans to come in contact with the Mexican grizzly were the conquistadors in the 16th century, when Francisco Vásquez de Coronado went on an expedition to find the Seven Cities of Gold. His expedition began in Mexico City in 1540, and went north to New Mexico and the Buffalo Plains in the modern-day U.S. states of Texas and Kansas. Because the bears hunted the cattle from time to time, they were considered as pests by farmers. Grizzlies were trapped, shot and poisoned, and had already become scarce by the 1930s. Its former range decreased to the three isolated mountains Cerro Campana, Cerro Santa Clara, and Sierra del Nido 80 km (50 mi) north of Chihuahua, within the State of Chihuahua. By 1960, only 30 of them were left. Despite its protected status, the hunting continued. By 1964, the Mexican grizzly was regarded as being extinct.[7] After rumours of some surviving individuals on a ranch at the headwaters of the Yaqui River in the state of Sonora in 1968, American biologist Dr. Carl B. Koford went on a three-month survey but without success.[9] A grizzly was shot in 1976 in Sonora, the fourth confirmed in Sonora, and the first in many decades.[10] The Mexican grizzly is now presumed to be extinct, or perhaps only extirpated.[11]


  1. ^ a b Merriam, C. H. (1914). "Descriptions of New Bears of North America". Proceedings of the Biological Society of Washington. Bulletin of the Biological Society of Washington. pp. 190–191. ISSN 1943-6327.
  2. ^ a b Ensayo, Rudo (1764). A Description of Sonora and Arizona in 1764. Retrieved 23 May 2015.
  3. ^ "Arkive closure". Archived from the original on 2017-07-05. Retrieved 2017-07-03.
  4. ^ Day, D. (1981). The Doomsday Book of Animals. London: Ebury Press. ISBN 0-670-27987-0.
  5. ^ Wright, Henry William (1913). The Grizzly Bear (1980 reprint ed.). University of Nebraska Press. p. 192.
  6. ^ "Mexican grizzly bear (extinct) – Bear Conservation". Retrieved 2019-04-04.
  7. ^ a b c Brown, David E. (1996). The Grizzly in the Southwest: Documentary of an Extinction. University of Oklahoma Press. ISBN 978-0-8061-2880-1. Retrieved 23 May 2015.
  8. ^ Pfefferkorn, Ignaz (1949). A description of the province. 12. University of New Mexico Press.[clarification needed]
  9. ^ Koford, C. B. (1969), The last of the Mexican grizzly bear, 2, IUCN Bulletin
  10. ^ Gallo-Reynoso, Juan-Pablo (2008). "Probable occurrence of a brown bear (Ursus arctos) in Sonora, Mexico, in 1976" (PDF). The Southwestern Naturalist. 53 (2): 256–260. doi:10.1894/0038-4909(2008)53[256:pooabb];2. Retrieved 23 May 2015.
  11. ^ Escalante, Tania; Espinosa, David; Morrone, Juan J (2003). "Using parsimony analysis of endemicity to analyze the distribution of Mexican land mammals". The Southwestern Naturalist. 48 (4): 563–578. doi:10.1894/0038-4909(2003)048<0563:UPAOET>2.0.CO;2.

Further reading[edit]

  • Julian Huxley, Martyn Bramwell et al.: The Atlas of World Wildlife, 1973
  • David Day: The Doomsday Book of Animals. Ebury Press, London 1981, ISBN 0-670-27987-0.
  • Jane Thornbark and Martin Jenkins: The IUCN Mammal Red Data Book. Part 1: Threatened mammalian taxa of the Americas and the Australasian zoogeographic region (excluding Cetacea). International Union for the Conservation of Nature, Gland Switzerland, 1982. p. 339
  • Walton Beacham: World Wildlife Fund Guide to Extinct Species of Modern Times, 1997, ISBN 0-933833-40-7
  • A. Starker Leopold: Wildlife of Mexico – The Game Birds and Mammals, 1959

External links[edit]