. These paintings are found on the south side of a large hill which is situation over an even large one and has a natural opening similar to a window. During part of the year, the sun’s rays pass directly through the “window” onto the sun image. The only other surface water is the Saucello, Los Encinos, Higuerillas and Del Buey arroyos, which generally do not flow during the dry season from March to June. The climate is dry and semi hot with an average annual temperature of 22C. Winters are distinguishable and freezes occur on occasion. The hottest months are from May to August when temperatures can rise to up to 40C. The average temperature year round is 21.7C. Annual precipitation, mostly restricted to the rainy season in late summer and early fall is about 435mm. The lowest areas, between 1200 and 1400masl has the driest climate with an average rainfall of about 300 to 400 mm yearly. Temperatures range from 2 to 35C with an average temperature of 22C. Winters are well defined and freezes appear about once every ten years. Between 1500 and 1800 masl, the conditions begin to change from semi desert to temperate forest. Temperatures vary from -3 to 35C with an average of 20C. Between 2000 and 3000masl, temperatures vary from -5 to 25C and rainfall of between 500 and 600mm. The municipality experiences about sixty cloudy days each year. Most of the vegetation consists of mesquite (prosopis spp) along with some pine-holm oak forest in the east and desert scrub brush on the extreme south. Other plants that can be found in the municipality include palo bobo (Tessaria integrifolia), uña de gato, huisache (Vachellia farnesiana), granjeno, palo sishote as well as nopal, wild oregano and barrel cactus. Wildlife is mostly limited to that which can live in arid conditions such as doves, turtledoves (Dove), quail, rabbits, squirrels, skunks, weasels, cacomistle, raccoons, badgers, coyotes, foxes, armadillos and various types of snakes including the coral snake and the rattlesnake. In the La Higuera and Río Blanco rivers there are various types of fish such as trout, tilapia, catfish and carp. In the forested areas, there are white-tailed deer, temazate (Mazama temama), wild boar, and pumas (Cougar). The Tembladera Lookout Point is situated on the side of Highway 120. The site allows for views of “biznaga” cactus which grow to up to 2.3 meters in height as well as views of mountains such as the Cerro de Media Luna, Cerro de la Virgen, El Picacho, Cerro el Capanario as well as the Del Paraiso Canyon, and the Extoráz River. Demographics and culture The military campaigns of the mid 18th century wiped out most of the Chichimecas except for some small communities. Otomi (Otomi people) families were brought into the area into settlements such as El Paraíso, Adjuntas de Higueras, La Higuera, El Puerto de la Guitarra, Agua del Ángel, El Pilón La Tinaja, El Carrizal and La Mesa del Troje. However, at their peak they only numbered about 550 inhabitants. Since that time, most of these small groups assimilated into the mainstream culture, losing the Otomi language and many emigrated out of the area, especially in the 20th century. As of the 2005 census, only fifty people who spoke an indigenous language at all lived in the municipality. About 6% of the municipality’s population was Otomi in 1900, but near zero now. In 2001, it was added to the International Networks of Man and Biosphere (Man and the Biosphere Programme) of UNESCO as the thirteenth Mexican reserve on the list, occupying first place in regards to ecodiversity. It is also recognized as a Área de Importancia para la Conservación de las Aves (Area of Importance for the Conservation of Birds) by the Consejo Internacional para la Preservación de las Aves Mexicanas.