The two mountain ranges dominate the 665,400-acre refuge, of which more than 80 percent is designated wilderness. Although these mountains are not especially high (the tallest peak is less than 5,000 feet), they are extremely rugged and rise sharply from the surrounding land, home to plant and animal species adapted to the harsh climate of the Sonoran desert.
Able to store large quantities of water in their leaves, stems or roots, cacti thrive in the desert climate. Towering saguaro cacti reach up to 50 feet in height and are perhaps the most distinctive cacti found on the refuge. Closer to the ground, prickly pear, cholla, hedgehog, pincushion, and barrel cacti, as well as desert night-blooming cereus, thrive. Palm Canyon, located in western region of the refuge, is well known for its native palms. California fan palms are probably remnants from when this area was wetter and cooler. Numbering less than 100, the handful of trees is among the only native palms in Arizona.
The vast desert environment is also host or home to numerous mammal species, the majority of which are nocturnal and forage at night during cooler temperatures. Scanning the horizon, the desert can appear devoid of animal life. Yet upon closer inspection, it reveals burrows among bushes, rocks, and even on the open plains -- home to badgers, foxes, ground squirrels, pocket mice, and kangaroo rats.
Most desert mammals, especially the smaller ones, have adapted to survive with little water and receive needed moisture from plant material. Water conservation is an absolute necessity to desert mammals like the ringtail and mountain lion. Larger animals like desert bighorn sheep and mule deer cope with extreme temperature during the day by staying within mountain caves and, in the case of the mule deer, finding respite under desert trees and overhanging banks. Bats, the only true flying mammals, find caves, crevices, and mines ideal places to roost and are rarely seen in the daylight.
Kofa National Wildlife Refuge supports numerous amphibians and reptiles. The elusive and venomous Gila monster is the largest land lizard native to the United States and might be spotted while driving or hiking on a cool morning on the refuge. The western diamondback rattlesnake, chuckwalla, desert horned lizard, desert iguana, and the red-spotted toad are also common refuge residents.
The refuge provides important habitat for a variety of birds. White-winged doves can be seen feeding on the saguaro’s red fruit while cactus wrens safely nest within the teddybear cholla, taking advantage of the cactus’ sharp spines for protection. Visitors may catch a glimpse of northern flickers, canyon towhees, phainopeplas, or Gambel’s quails near water sources and, high above, turkey vultures or golden eagles can occasionally be seen soaring.