Grizzlies / North American brown bears

[BorneanTiger]

Apart from the Californian grizzly, 2 other populations of grizzlies also became extinct, or at least invisible from our sight: the Mexican grizzly and the Ungava or Labrador grizzly.

Mexican grizzlies at the Field Columbian Museum, 1919. From: “The grizzly, our greatest wild animal” by Enos Abijah Mills (1870–1922): http://www.bearconservation.org.uk/mexic...y-extinct/
   

Starting with the Mexican grizzly, it was formerly given the scientific name Ursus arctos nelsoni by Clinton Hart Merriam in 1914. It was smaller than the brown bears of the northern USA and Canada. Male bears weighed up to around 315 kgs (694.46 lbs), with females being smaller. Length was around 180 cms (5.91 ft). Colour varied from pale buff-yellow to a grizzled grey or white, which would appear silver in bright sunlight, hence the bear’s Mexican name of “el oso plateado” (the silver bear). It was found in the northern territories of Mexico, particularly in the northern savannah and mountain forests, and northwards into New Mexico and Arizona in the USA. As for the bears of Baja California, they are treated as being of the Californian population of grizzlies: https://books.google.com/books?redir_esc...ia&f=false

Historic grizzly range c. 1850 (light green), remaining range c. 1920 (dark green), & approximate dates of local extirpations, where known. Probable extent of Mexican grizzly range edged in red. Credit: D. Mattson, unpublished data, edging Bear Conservation.
   

It inhabited temperate grasslands and mountain pine forests, besides being adapted to survive the arid conditions of the Sonoran Desert and canyonlands. It probably had a natural lifespan of around 25 years in the wild. In common with other brown bears, the Mexican grizzly was an omnivore eating plants, fruits, insects, small mammals and carrion. It seems unlikely that the bears would have hibernated, although they may have spent some time in winter dens. Females produced one to 3 cubs, which would remain with them for around 2 ½ years, during which the mother would not become pregnant again. Except during mating, and for mothers with cubs, the bears were solitary. With the expansion of cattle farming within the Mexican brown bear’s range, the animals increasingly came to be considered by cattle farmers as pests, and were thus trapped, shot and poisoned. The situation deteriorated rapidly in the early 20th century, and the population was rare by the 1930s. Ultimately, their range was reduced to the isolated mountains of Cerro Campano, Santa Clara and Sierra del Nido, and by 1960, it was believed that only 30 bears or less remained. Although the bears were protected, illegal hunting and persecution continued. By 1969, probably sooner, the population was apparently extinct. From time to time, there have been rumoured sightings of lone animals, and in 1980, Trevino & Jonkel published a report indicating that grizzly bears might still be present in Mexico, see: http://wildsonora.com/sites/default/file...n-1976.pdf, http://www.bearconservation.org.uk/Do%20...Jonkel.pdf 

There have been no further substantiated sightings of Mexican grizzlies. Reply