Luís Río Colorado and Plutarco Elías Calles. This area has been considered one of the most arid and inhospitable of the Sonoran Desert. In spite of this, the area contains a wide variety of wildlife and evidence of human habitation from ancient times, which has attracted the attention of both tourists and researchers. It contains 553 species of plants with cactuses such as saguaros, chollas and ocotillos dominating. With the rainy season, the area explodes with short-lived wildflowers. The area also contains 41 species of mammals, 237 species of birds, 45 species of reptiles, and four types of amphibians. It was declared a protected biosphere reserve by the Mexican government in 1993. The entrance to the biosphere park is located 50 km from the city of Puerto Peñasco. The nucleus of the biosphere consists of the Sierra el Pinacate, Adair Bay and Sierra del Rosario which cannot be developed under any circumstances. The main attraction for tourists is the volcanic craters. The major ones are named Badillo, Molina (or Trébol), McDougal (the largest) and Caravajales. In addition, there is the Grande Volcano which stands at 3,200 feet tall, and has a depth of 950 ft. San Jorge Island, also known as Bird Island, is really a small group of rocky outcroppings that are just above the surface of the sea about 40 km southeast of the city. The rocks are capped in white like the Alps, not with snow, but with the guano of innumerable sea birds such as seagulls and pelicans, which live here. Below the birds live approximately 3,000 sea lions very close to the water. It is the largest concentration of sea lions in Mexico. It is possible to kayak and/or snorkel here. Nine native cultures can be found in the municipality. The Guarijíos have a wide variety of crafts such as figures made with natural materials such as palm fronds and clay. They also make hats from a variety of natural fibers. The Mayos, who call themselves the Yoreme, have a rich oral tradition. Other groups include the Opatas, the Papagos, the Pimas, the Seris, the Yaquis, the Cucapa, and the Kikapu, all of whom are noted for basketmaking using desert plants. References Municipalities of Sonora