Tadarida australis
white-striped free-tailed bat

Tadarida australis (white-striped free-tailed bats) occurs naturally in Australia. These bats range through the entire continent, excluding the northern coastal area. (Hall and Richards, 1972; Strahan, 1995)

During Australia's coldest months (June through August), these bats migrate north to areas with warmer nighttime temperatures and, therefore, higher insect populations. (Bullen and McKenzie, 2005)

White-striped free-tailed bats can be found in lowland, tropical and scrub forests. They roost in dead, hollow trees or tree stumps and in attics of buildings, barns, and silos in human-dominated landscapes. (Lumsden and Bennett, 1995; Strahan, 1995)

Considered the largest Australian molossid, T. australis individuals weigh up to 40 g and have a maximum length of 100 mm. Forearm length ranges from 57mm to 63mm and the tail extends 55mm from the body. The large, forward pointed ears can be 25mm in length. A short tragus is present. The upper lip is deeply wrinkled, and these bats have single incisors on each premaxilla. Both sexes have a throat pouch. (Menkhorst and Knight, 2001; Strahan, 1995)

Fur color varies from chocolate brown to dark brown dorsally and lighter ventrally. The common name, white-striped free-tailed bat, refers to a characteristic symmetrical pattern of white fur on the body. This runs from the front to the back where the wings fold against the torso. As a member of the family Molossidae, T. australis has a free tail extending through a well-formed tail membrane (uropatagium). (Strahan, 1995)

No information on the lifespan of this species was found. In Tadarida brasiliensis, a related species, female lifespans have been documented at about seven years. (Walton and Richardson, 1989)

White-striped free-tailed bats fly fast and high above tree canopies as they forage and travel. Their high and fast flight makes them difficult to capture and study. They are nocturnal, hunting at night and roosting during the day. Unlike some other bats, T. australis has adequate ground mobility and doesn’t seem to have difficulty “running." Considered mainly solitary, T. australis may be found in small groups of ten. White-striped free-tailed bats do not hibernate, but do enter torpor. (Bullen and McKenzie, 2005; Herr, 1998; Menkhorst and Knight, 2001; Strahan, 1995)

Home Range

The home range size of T. australis has not been documented.

Tadarida australis uses echolocation to detect flying insects, and is one of the few bat species with calls audible to human ears. They mainly use constant frequency echolocation but some frequency modulated components have been recorded as well. The constant frequency calls range in bandwidth from 10.5 to 15 kHz. Tactile sense has developed to detect when prey come into contact with the uropatagium, which is an important feature for capturing insects. Molossidae species reflexively close their mouths when insect prey brush the hairs near their jaws. Although T. australis uses its uropatagium when capturing ground and aerial prey, it is also likely to use the same reflexive jaw-shutting behavior as other Molossidae. (Bullen and McKenzie, 2005; Herr, 1998; Menkhorst and Knight, 2001; Strahan, 1995; Walton and Richardson, 1989)

Little research has been done on communication in white-striped free-tailed bats. As in most mammals, chemical and auditory communication is likely to be important.

Tadarida australis is insectivorous. These bats mainly capture insects in flight but may also walk on the ground and foliage to capture insects on surfaces. (Strahan, 1995)

Macroderma gigas, Australian false vampire bats, may prey on T. australis and the remains of T. australis have been found in pellets of Ninox strenua, powerful owls. (Bullen and McKenzie, 2005)

Tadarida australis plays a crucial role in regulating insect populations.

There are no known adverse effects of T. australis on humans.

Insectivorous bats, such as white-striped free-tailed bats, can limit populations of agricultural insect pests. Bat guano is also valuable as fertilizer.

The IUCN lists T. australis as at lower risk for endangerment. Deforestation results in loss of roosting and foraging sites. Also, pesticides can accumulate in the bodies of these insectivorous bats and threaten many species of bats.