The diversity of habitats in the park, including permanently flowing water at Rattlesnake Springs, provides for an exciting array of wildlife. This diversity is further benefited by the position of the park at the intersection of the southern Rocky Mountain, northern Chihuahuan Desert, and southwestern Great Plains biogeographic provinces.
Many animals occur here at the geographic limits of their ranges. For example, several species of reptiles are at the edges of their distributions.
The deserts of the Southwest contain some of the highest diversities of mammals, birds, reptiles, and insects in the United States. The park provides important year-round habitat for top predators such as cougars, and nesting habitat for migratory species such as the large colonies of cave swallows and Brazilian (Mexican) Free-tailed bats that raise their young in Carlsbad Cavern.
Rattlesnake Springs, a rare desert wooded riparian area that has been designated an Important Bird Area (IBA) by the National Audubon Society, draws birders from around the world to see some of the 300-plus species that have been noted there. The Carlsbad Cavern Natural Entrance is also an Audubon IBA because of the large colony of cave swallows that resides and breeds there in the summer.
For more more information on the National Audubon Society's IBA program, see their website at www.audubon.org/bird/iba/index.html.
Current checklists for park fauna identify 67 species of mammals (including 17 species of bats), 357 species of birds, 55 different reptiles and amphibians, 5 species of fish, and an incomplete list of over 600 insects, with more identified each year.