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; 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)
Social behavior in this species has not been reported. They are considered mainly solitary, but they may roost together in small groups of up to ten. Maternity roosts can reach numbers up to one hundred. Ellis (1993) suggested that these bats may fly into each other as some type of courtship. (Ellis, 1993; Strahan, 1995)
Female white-striped free-tailed bats synchronize copulation and ovulation. Mating occurs in August, as females are monoestrous, and birth occurs in December or January. Females give birth to a solitary offspring. Males attain sexual maturity after one and a half years, whereas females reach maturity at nine months. (Kitchener and Hudson, 1982)
Parental investment is not well documented, however, as in most bat species, females are likely to be the sole caregivers for their offspring. (Kitchener and Hudson, 1982)
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)
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.
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; Bullen and McKenzie, 2005)
Tadarida australis plays a crucial role in regulating insect populations.
Insectivorous bats, such as white-striped free-tailed bats, can limit populations of agricultural insect pests. Bat guano is also valuable as fertilizer.
There are no known adverse effects of T. australis on humans.
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.
Tanya Dewey (editor), Animal Diversity Web.
Nathaniel Minnick (author), University of Michigan-Ann Arbor, Phil Myers (editor, instructor), Museum of Zoology, University of Michigan-Ann Arbor.
Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.
uses sound to communicate
living in landscapes dominated by human agriculture.
young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.
Referring to an animal that lives in trees; tree-climbing.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
an animal that mainly eats meat
uses smells or other chemicals to communicate
The process by which an animal locates itself with respect to other animals and objects by emitting sound waves and sensing the pattern of the reflected sound waves.
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.
An animal that eats mainly insects or spiders.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
makes seasonal movements between breeding and wintering grounds
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.
scrub forests develop in areas that experience dry seasons.
breeding is confined to a particular season
reproduction that includes combining the genetic contribution of two individuals, a male and a female
living in residential areas on the outskirts of large cities or towns.
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
Living on the ground.
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
uses sound above the range of human hearing for either navigation or communication or both
living in cities and large towns, landscapes dominated by human structures and activity.
uses sight to communicate
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
Bernard, R., G. Cumming. 1997. African bats: Evolution of reproductive patterns and delays. The Quarterly Review of Biology, 72/3: 253-274.
Bullen, R., N. McKenzie. 2005. Seasonal range variation of Tadarida australis (Chiroptera: Molossidae) in Western Australia: the impact of enthalpy. Australian Journal of Zoology, 53: 145-156.
Ellis, M. 1993. Unexplained behaviour in the white-striped mastiff-bat Tadarida australis. Australian Zoologist, 29/1-2: 103-104.
Hall, L., G. Richards. 1972. Notes on Tadarida-Australis Chiroptera Molossidae. Australian Mammalogy, 1: 46-47.
Herr, A. 1998. "Aspects of the ecology of insectivorous forest-dwelling bats (Microchiroptera) in the western slopes of the Australian alps" (On-line pdf). Accessed March 21, 2006 at http://csusap.csu.edu.au/~aherr/thesis/thesis.pdf.
Kitchener, D., C. Hudson. 1982. Reproduction in the Female White-Striped Mastiff Bat, Tadarida australis (Gray). Australian Journal of Zoology, 30: 1-14.
Lumsden, L., A. Bennett. 1995. Bats of a semi-arid environment in South-eastern Australia: Biogeography, ecology and conservation. Wildlife Reserve, 22: 217-240.
Lumsden, L., A. Bennett. 2005. Scattered trees in rural landscapes: foraging habitat for insectivorous bats in south-eastern Australia. Biological Conservation, 122/2: 205-222.
Menkhorst, P., F. Knight. 2001. A Field Guide to the Mammals of Australia. Oxford: Oxford University Press.
Strahan, R. 1995. The Mammals of Australia. Australia: Reed Books.
Tidemann, C., S. Flavel. 1987. Factors affecting choice of diurnal roost site by tree-hole bats (Microchiroptera) in South-Eastern Australia. Australian Wildlife Reserve, 14: 489-73.
Tilley, S. 1982. The diet of the powerful Owl, Ninon strenua, in Victoria. Australian Wildlife Reserve, 9: 157-175.
Walton, D., B. Richardson. 1989. Fauna of Australia Volume 1B: Mammalia. Canberra: Australian Government Publishing Service.