The western mastiff bat (Eumops perotis), also known as the western bonneted bat, the greater mastiff bat, or the greater bonneted bat, is a member of the free-tailed bat family, Molossidae. It is found in the Western United States, Mexico and South America. This species is the largest bat native to North America, and some of its distinguishing characteristics are its large ears, wings, and forearms. The subspecies Eumops perotis californicus is a species of concern as identified by the U.S. Fish and Wildlife Service. The range of this subspecies is principally southwest desert regions of the United States, along the border with Mexico; however, the range extends as far north on the Pacific coast as Alameda County, California. Range and habitat The western mastiff bat is located in both South America and North America. In South America, the species is found in Brazil and its neighboring countries, ranging southward to northern Argentina. It can also be found in Cuba. The subspecies in North America, Eumops perotis californicus, resides in the southwestern United States (California, Arizona, New Mexico, Texas) and ranges southward to parts of central Mexico. The greater mastiff bat prefers to live in habitats with open space. Some examples include desert scrub, woodlands, and grasslands. Roosts are commonly located in crevices of rocky areas, such as cliffs and canyons, and have also been found within man-made structures such as buildings and tunnels. As the western mastiff bat cannot take off from flat surfaces, these spots are at least 3 meters above ground, providing the bat with sufficient space to drop from and take flight. Description Eumops perotis is most notable for its size, as it is the largest North American bat. It has a body length of and a wingspan of over . The body mass of this species can range from . The wings are long yet narrow, which limits the species' maneuverability in the air. The body mass of this species can range from . A defining characteristic is its large ears that range between and extend over the bat's snout. It also has large forearms with a length of . Males are larger than females and also have an odoriferous gland on their throat, which is less developed in females. The western mastiff bat is mostly dark in color, as the body is primarily brown or gray, though the underside is a lighter color. Ecology