Nyctinomops macrotis
big free-tailed bat

The big free tailed bat has been found as far north as southwestern British Colombia and as far east as South Carolina. Nyctinomops macrotis ranges from southwestern North America, through northern and central Mexico, throughout South America. It has also been found on Cuba, Jamaica, and Hispanola.

(Parish, D.A., 1999; Nowak, 1999)

Nyctinomops macrotis mainly inhabits rugged and rocky terrain. They are a migratory species that travels seasonally from Mexico to the southwestern United States (Texas, Arizona, California, Nevada, Colorado) . They prefer rocky cliffs in weathered rock fissures and crevices. They have also been discovered roosting in buildings and in terrestrial plants including ponderosa pines, douglas firs, and desert shrubs.

A nursery colony in the Chisos mountains in Brewster County, Big Bend National Park has become quite famous.

( http://www.nsrl.ttu.edu/tmot1/nyctmacr.htm)

(Nowak, 1999)

Adult males of this species range in head-body length from 145-160 mm, females are smaller (120-139 mm, approx. avg. 132).

The coat of Nyctinomops macrotis is very velvety, glossy, seemingly almost greasy to the touch. The coat is bi-colored, dorsally dark red to dark brown and ventrally substantially lighter.

The wings are long and narrow, and the membrane of the wing is thin and leathery. The tail extends freely somewhere between 40 to 52 mm behind the small tail membrane. The face of Nyctinomops macrotis is black; the ears lay forward and are joined at their bases on top of the head; the muzzle is fairly thin; and the upper lip is very furrowed. The legs of Nyctinomops macrotis are short and very strong.

The dentition of Nyctinomops macrotis is: 1/2 1/1 1/2 3/3

( http://www.ukans.edu/~mammals/nyctic-macr.html;

http://www.nsrl.ttu.edu/tmot1/nyctmacr.htm; Nowak, 1999)

Once impregnated the females and males tend to part ways. Females separate themselves from the males, and each of the sexes form cave colonies amongst themselves

( http://www.nsrl.ttu.edu/tmot1/nyctmacr.htm; Parish, D.A. and Jones C., 1999;

Nowak, 1999; Klingel, J., 2000 http://www.fw.vt.edu/fishex/nmex_main/species/050037.htm)

The mating season for Nyctinomops macrotis lasts for only a few weeks in the mid to late winter. The female gives birth to a single young sometime in early to mid summer, in mid to late June..

( http://www.nsrl.ttu.edu/tmot1/nyctmacr.htm;

Parish, D.A. and Jones C., 1999; Nowak, 1999; Klingel, J., 2000 http://www.fw.vt.edu/fishex/nmex_main/species/050037.htm)

The care of the infant is the responsiblity of the females. After conception, the females rely partly on stored body fat and their colony to provide for the unborn infant. After birth, the lactating female provides for her offspring until it is able to function as an adult, which takes somewhere in the range of 2 to 3 months. The development of the offspring is quite rapid; a young bat is very close to full grown and able to fly by October, at an age of 3 to 4 months.

( http://www.nsrl.ttu.edu/tmot1/nyctmacr.htm; Parish, D.A. and Jones C., 1999;

Nowak, 1999; Klingel, J., 2000 http://www.fw.vt.edu/fishex/nmex_main/species/050037.htm)

Nyctinomops macrotis is strictly nocturnal. It only leaves the roost after sundown to forage for food. They are solitary hunters for the most part but have been known to hunt in small groups. They are particularly strong fliers and have a tendency to wander, which can put them into residential homes. This also may cause the extremes of their geological range. Nyctinomops macrotis tends not to be that aggressive, but do attempt to bite if cornered or handled.

(Parish, D.A. and Jones C., 1999; http://www.nsrl.ttu.edu/tmot1/nyctmacr.htm)

The big free tailed bat feeds primarily on large moths, though it has been known to hunt ground dwelling insects including crickets, stinkbugs, and flying ants. They can be heard when hunting emitting a piercing chatter (audible to humans at a range over 20 kHz)

( http://www.nsrl.ttu.edu/tmot1/nyctmacr.htm;

Parish, D.A. and Jones C., 1999; Best, T.L.,Harvey M.J., Altenbach J.S., and Sanchez-Brown, T., http://talpz.unm.edu/batcall/accounts/accountsbase/nyma.html)

Big free tailed bats probably help control populations of pest insects.

Nyctinomops macrotis is not endangered, but is not common either.

Temperate North American bats are now threatened by a fungal disease called “white-nose syndrome.” This disease has devastated eastern North American bat populations at hibernation sites since 2007. The fungus, Geomyces destructans, grows best in cold, humid conditions that are typical of many bat hibernacula. The fungus grows on, and in some cases invades, the bodies of hibernating bats and seems to result in disturbance from hibernation, causing a debilitating loss of important metabolic resources and mass deaths. Mortality rates at some hibernation sites have been as high as 90%. While there are currently no reports of Nyctinomops macrotis mortalities as a result of white-nose syndrome, the disease continues to expand its range in North America. (Cryan, 2010; National Park Service, Wildlife Health Center, 2010)

The species Nyctinomops macrotis was recently transferred to the genus Nyctinomops from Tadarida.

In the civil war guano was collected and used as a base compound to make gunpowder by the Confederate army.

( http://www.ukans.edu/~mammals/nyctic-macr.html; Nowak,1999)