Querétaro has a number of areas which lend themselves to ecotourism. One area especially promoted is the Sierra Gorda region. The area is a complex of canyons and mountains extending over 400,000 hectares with a well conserved biological diversity. In the deep canyons there are grottos, valleys, ravines and arroyos. In the higher areas there are forests of pines and holm oak, and tropical forests in the lower elevations. The area was declared a biological reserve and contains about 1,700 species of plants, some endemic only to the area. There are also 360 species of birds, 130 of mammals, and just over 100 of amphibians and reptiles. A number of these are in danger of extinction such as macaws, the black bear, the porcupine and the spider monkey.