National preserve, southwestern New Mexico, U.S. Located in the Gila National Forest near the headwaters of the Gila River, it contains groups of small but well-preserved Pueblo Indian dwellings in natural cavities of an overhanging cliff 150 ft (45 m) high. The dwellings were inhabited AD 100-1300. Established in 1907, the monument occupies 533 acres (216 hectares)
A river rising in the mountains of western New Mexico and flowing about 1,014 km (630 mi) generally westward across southern Arizona to the Colorado River at Yuma in the southwest corner of the state. River, New Mexico and Arizona, U.S. Rising in southwestern New Mexico in the Elk Mountains, near the Gila Cliff Dwellings National Monument, it flows 630 mi (1,015 km) west over desert land to the Colorado River at Yuma, Ariz. Coolidge Dam (1928) on the Gila near Globe, Ariz., is used for irrigation; the dam, together with Roosevelt Dam on the Salt River, stores all available surface water, so the Gila riverbed is dry down to the Colorado. Its valley is the chief habitat of the Gila monster
One of the only two species (both in the family Helodermatidae) of venomous lizards, named for the Gila River basin and found in the southwestern U.S. and northern Mexico. The Gila monster (Heloderma suspectum) grows to about 20 in. (50 cm) long, is stout-bodied with black and pink blotches or bands, and has beadlike scales. During warm weather, it feeds at night on small mammals, birds, and eggs and stores fat in the tail and abdomen for the winter. It is sluggish but has a strong bite. The venom (a neurotoxin) is conducted along grooves in the teeth from glands in the lower jaw. Bites are rarely fatal to humans. The other venomous species is the Mexican beaded lizard (H. horridum)