The Arizona myotis (Myotis occultus) is a small brown bat that is found across a number of U.S. states, including Arizona, New Mexico, California, Colorado, Utah, and Texas, as well as parts of northern Mexico. It generally prefers to live near large bodies of water, like rivers and lakes, and at high elevations, around 1,800−2,200 meters (6,000–9,000 feet), although can also be found in lowland regions. In the summer, males and females roost in separate places, and in the winter the Arizona myotis can be found hibernating in large groups with other species of bats. When choosing roost sites, these bats now sometimes make use of some human structures. The Arizon myotis can be found under bridges and in old mine shafts and buildings in some parts of its range.

The Arizona myotis is considered common, but its numbers may be declining in some areas. Some scientists suspect pesticides may contribute to population loss. Several known roosting sites have become inactive in recent years, possibly due in part to human disturbance. A relatively new species, the Arizona myotis was only classified as its own species in 2005, due to new DNA evidence and body size measurements. As a result, scientists know little about its biology, population size, or threats. However, they do know that Arizona myotis are voracious eaters; a single bat can eat 600 mosquitos in a single night.

  1. Why do scientists still have questions about the Arizona myotis?

    • Answer

      It is a new species and has not been studied intensely yet.

  2. Why might the Arizona myotis be beneficial to humans?

    • Answer

      They eat a lot of pests. A single Arizona myotis can eat up to 600 mosquitoes in a single night.

  3. How have Arizona myotis adapted to human presence?

    • Answer

      Arizona myotis can be found roosting in human constructions such as bridges, buildings, and mine shafts.


study of living things.


to identify or arrange by specific type or characteristic.


(deoxyribonucleic acid) molecule in every living organism that contains specific genetic information on that organism.


height above or below sea level.


to reduce activity almost to sleeping in order to conserve food and energy, usually in winter.


total number of people or organisms in a particular area.


perch (often a pole or branch) where birds or bats rest.


eating or hungering for large amounts of food.