Fat lizard with long tail on a black rock.

Great Basin collared lizard (Crotaphytus bicinctores)

NPS/John Spence

The wildlife of the Colorado Plateau desert have developed unique adaptations to the arid conditions of their environment and are a part of the rich diversity of life in Glen Canyon National Recreation Area (NRA). Wildlife in Glen Canyon NRA is a reflection of the Colorado Plateau, changes in land use, and changes in the environment caused by the completion of Glen Canyon Dam in 1963 and subsequent filling of Lake Powell. In addition to playing vital roles in the desert ecosystem and animal communities, wildlife also provides recreational opportunities such as bird watching and fishing.

The habitats of Glen Canyon NRA support a diverse range of animals: birds, fish, mammals, amphibians, and reptiles. Over 300 species of birds have been documented in the area. This diversity of species was unknown prior to construction of the dam and can be attributed to the colonization of Lake Powell by aquatic birds and migratory birds. Despite the high diversity of species, few breeding populations exist at Glen Canyon. The bare rocks, cliffs, slickrock, and shrubland communities that comprise over 77% of the landscape do not provide suitable breeding habitat for many birds. Further, little aquatic breeding habitat exists because of lake level fluctuations which prevent aquatic vegetation from establishing.

Over time, native fish adapted to thrive in the shallow, muddy waters of the Colorado River which experienced heavy flooding in the spring. There are eight native fish unique to the Colorado Basin (endemic). Three are endangered. The creation of Lake Powell drastically altered habitats in Glen Canyon. Where the warm waters of the Colorado River once ran prior to 1963, is now the cool, calm water of Lake Powell, an oligotrophic lake poor in nutrients. Native species can be found in the flowing portions of the Colorado and other rivers in Glen Canyon NRA, which resemble the habitat and conditions of the Colorado River system before construction of dams. Though native species are struggling, Lake Powell created habitat for nonnative sport fish that provide outstanding recreational fishing opportunities.

Adaptations such as temperature control and water conservation help mammals survive the heat. Small mammals are more common than larger mammals in a desert environment because of their lower energy requirements, rates of heat loss, and food and water needs. Small mammals such as kangaroo rats and rabbits will get most or all of their water from the vegetation they eat. Of the 64 mammals documented in Glen Canyon NRA, bats, rodents, and other small mammals are the most commonly observed. Jackrabbits, bighorn sheep, coyote, and also occur in the area.

To conserve energy, many desert dwellers, including amphibians, will become more active at night when the temperature cools. The damp, soft skin of amphibians helps regulate temperature and moisture, but leaves them vulnerable to extreme heat and drought. Frogs and toads, which comprise five of the six known amphibian species in Glen Canyon NRA, are more active at night to conserve moisture and energy. Amphibians in Glen Canyon include the canyon treefrog, northern leopard frog and spadefoot toads.

Like amphibians, reptiles are cold-blooded and will spend the hottest parts of the day in the shade of bushes, tree trunks, and crevices to regulate their temperature. At least 28 reptile species are found in Glen Canyon NRA. The chuckwalla is the largest lizard documented in the area and has loose baggy skin that can be inflated to wedge itself between rocks when threatened. There are at least four western rattlesnake subspecies present and all are venomous. Rattlesnakes, like other reptiles, will avoid being detected if possible but may strike if threatened. To observe a reptile, locate suitable habitat for the species, then watch and listen for small movements on rocks or in vegetation.

Several rare and federally listed species use Glen Canyon NRA: the Mexican spotted owl, southwestern willow flycatchers, the northern leopard frog, Colorado pikeminnow, humpback chub, and razorback sucker. Native species are an integral part of the Colorado Plateau ecosystem. Continued scientific study and observation will add to our understanding of animal communities, importance of native species, and impacts of exotic species. A lizard scurrying across sand or a bird in flight can be exciting reminders of the wildlife that is hidden in the desert. Bring your binoculars and take our species checklists on your next exploration of the vast, rugged landscape of Glen Canyon NRA.

For more in depth information on the animals and other natural resources of Glen Canyon NRA, explore the links under Nature & Science or follow the links on this page. Species checklists are available for animals and plants.

Published 8/07

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