Nyctinomops femorosaccus
pocketed free-tailed bat

Nyctinomops femorosacca, the Pocketed Free-tailed Bat, is a member of the Molossidae. It inhabits the southwestern United States and northwestern Mexico. The bat has been seen in southern Arizona, southern California, southeastern New Mexico, western Texas, and into Mexico to the state of Michoacan. (http://www.nsrl.ttu.edu/tmot/nyctfemo.htm )

This species inhabits semiarid desertlands. Their roosts can be found in caves, tunnels, mines, and rock crevices. They have also been found hanging under the roof tiles of buildings. They are usually found in large colonies. (Vaughn, Ryan, Czaplewski, 1999)

The Pocketed Free-tailed Bat has a large broad head with grooved lips. The face has many stiff hairs with spoonlike tips. A tragus is present and the ears are thick and leathery. These ears are joined in the middle of the forehead. The length of the bat on average is approximately 112mm. The feet are 10mm, the tail is 46mm, the ears 23mm, and the forearms are 46mm. The nasals are located on the nasal protuberance and no nose leaf is present (Grzimek, 1990). The wings are long and narrow. The tail extends well beyond the edge of the uropatagium. The fur is short. A fold of skin stretches from the inner side of the femur to the middle of the tibia. Ths fold produces a pocket on the underside of the interfemoral membrane, which gives the animal its common name, the Pocketed Free-tailed Bat. The dental formula is 1/2, 1/1, 2/2, 3/3=30, with the incisors placed close together. ( http://www.nsrl.ttu.edu/tmot/nyctfemo.htm )

These bats leave their roost late in the evening or early night to forage. They are very swift and have powerful flight. Krutzsch recorded the following observations on a colony of 50-60 Pocketed Free-tailed Bats: a daytime roost was located in the crevice of the face of a cliff in San Diego, CA. The first bats left at approximately 6:15 p.m., and others followed in twos and threes for another half and hour. They dropped from 1 to 1.5 meters before taking wing. The flight was rapid, with complete wing beats. When first taking flight, they uttered a high pitched, chattering call, which was repeated while in flight. They also called a lot while in the roost. (http://www.nsrl.ttu.edu/tmot/nyctfemo.htm)

This species of bat is strictly insectivorous. Peak activity for feeding occurs at two different times, at the beginning of the night, and again at the end. Like many bats, the Pocketed Free-tailed Bat uses echolocation to detect the presence of its prey. (Grzimek, 1990). They catch their food in mid-flight. They typically eat moths, crickets, flying ants, stinkbugs, froghoppers, and lacewings. (httm://www.nsrl.ttu.edu/tmot/nyctfemo.htm)

They are insectivorous and play a part in controlling many of the pesky insects that destroy plants and crops.

The status of the Pocketed Free-tailed Bat is not known. They are undoubtedly being threatened by the habitat modification and pesticide dispersal by humans. (Grzimek, 1990) There are no conservation projects underway specifically for Nyctinomops femorosacca.

Males of this species have chest and throat glands. The echolocation signals are short and are emitted through the mouth. Their enemies include humans, diurnal and nocturnal birds of prey, and parasites. (Grimek, 1990). There is limited information on this particular species of bat.