Bats (Order Chiroptera)
Bats are the only mammals capable of true flight. This is accomplished by modification of the long bones of the arm and hand into a wing. Also, the hind limbs are rotated such that the knee joint bends backward instead of forward. The small eyes of the bat contribute little to visual orientation; rather, bats have well-developed ears that allow them to use echolocation for orientation as well as for hunting insects in flight. All species of bats that occur in the White Mountains are insectivorous. Two survival mechanisms are exhibited by bats during the winter, when insects are absent. Some species migrate to more favorable regions, returning months later to their summer ranges. Other species hibernate during the winter to minimize energy expenditure when food is scarce. The following bat species are known from records to occur in the White Mountains: Long-eared Myotis (Myotis evotis) , Hairy-winged Myotis (Myotis volans) , Small-footed Myotis (Myotis subulatus) , Western Pipistrelle (Pipistrellus hesperus) , and Big Brown Bat (Eptesicus fuscus) . Species that are likely to occur at least seasonally in the White Mountains include: Little Brown Myotis (Myotis lucifugus) (Fig. 12.2), Yuma Myotis (Myotis yumanensis) , Fringed Myotis (Myotis thysanoides) , California Myotis (Myotis californicus) , Leib's Myotis (Myotis Leibii) , Hoary
Bat (Lasiurus cinereus) , Silvery-haired Bat (Lasionycteris noctivagans) , Pallid Bat (Antrozous pallidus) , Brazilian Free-tailed Bat (Tadarida brasiliensis) , and Western Big-eared Bat (Plecotus townsendii) .