The species is the only Australian bat that preys on large vertebrates – birds, reptiles and other mammals – which they detect using acute sight and hearing, combined with echolocation, while waiting in ambush at a perch.
The wing membrane and bare skin is pale in colour, their fur is light or dark grey over the back and paler at the front.
The family all have large eyes, a nose-leaf and tragus, long ears joined at the base, and are also found in southern Asia and central Africa.
[2][3] A revision of bat genera by Gerrit Smith Miller Jr. reassigned the species to a new genus Macroderma, creating the current generic combination.
An arrangement separating a "Pilbara district" population as subspecies Macroderma gigas saturata is noted as synonymous with this species concept (MSW 3rd ed., 2005).
[2] An earlier observation had been noted by Robert Austin in 1854 at Mount Kenneth while surveying the inland regions of Western Australia.
[16] The nasal appendage is presumably similar in usage to the elaborate forms of the horse-shoe and leaf-nosed bat genera, manipulating, directing and receiving echolocation signals to detect prey.
[17] The teeth and short robust jaw allow the consumption of a wide variety of animals, either the flesh and bones of other vertebrate species or hard shells of larger invertebrates.
[20] The voice is audible to humans, one sound resembles the avian species Petrochelidon ariel (fairy martin) and transliterated as 'dirrup dirrup'.
Field observations at Pine Creek using nightscope equipment reported seeing M. gigas suspended from a tree and dropping to catch large locusts detected moving through grass at ten to twenty metres distance.
[24] The budgie is a favoured food of the bat, which they detect by the flock's chatter while retiring for the night, and these are taken to a perch to be consumed head first; the feet and wing parts are discarded while butchering the bird.
The sharp teeth and strong jaws are able to subdue animals as large as the bar-shouldered dove, species Geopelia humeralis, that may weigh as much as 150 grams, although most prey is smaller.
[26] A study of the avian prey of the bat revealed that over fifty species of birds are targeted, in a range of sizes but a preference for those weighing less than 35 grams.
[6] Remains of the species have been found with other mammals at the Devils Lair archaeological site in Southwest Australia, including other predators such as Thylacinus cynocephalus and Sarcophilus harrisii that inhabited the region after the first peoples had arrived.
[32] The mine was dug in the late nineteenth century and later occupied as a creche when it became unprofitable, however, it remains on a lease that may be profitable as an open-cut operation.
[35] Built environments may be used as feeding grounds,[6] but the ghost bat selects daytime roosts in caves, sheltered rock crevices, boulder piles or disused mines; occupation of abandoned buildings is only occasionally reported.
[12] Macroderma gigas favours these caves with multiple entrance ways as they are large enough to accommodate the greater wingspan of the species and allow an alternative exit when sensing a threat.
[9] Attempts to survey the distribution range began in 1961, when its earlier status as a relict and rare species was revised to indicate it was more widespread and disappearing in regions where it was known within living memory;[9] Hedley Finlayson interviewed Pitjanjarra elders (Anangu people) who knew of the species in the Musgrave, Mann and Tomkinson Ranges and not seen for forty years.
There are isolated congregations of bats in specified maternity sites in which the alleles expressed by the females are distinguishable; this implies that the separation of such populations extends through evolutionary time.
[6] The decline has been correlated to the increasing range of the amphibian species Rhinella marina (Bufo marinus), known locally as the cane toad.
[42] During the breeding season, late October to early November, female bats congregate in groups and give birth to a single young.
These congregations include introduced species, cane toad Rhinella marina, feral cats and foxes, and natives such as pythons, birds of prey, quolls and large frogs of genus Litoria.
[25] The species is vulnerable to several anthropogenic hazards, one is barbed wire fencing that accounts for many deaths when they are snagged through the easily torn wing membrane while in flight.
The damage caused by the barbed wire strands, often left littering their environment, is greatly increased as the individual become entangled as it attempts to dislodge itself.
[47] A study in the Pilbara region identified this as an especial concern, with indications that barbed wire was significantly impacting local populations when erected.
[1] They are especially sensitive to disturbance in wintering roosts, and a single fleeting visit will see the site deserted for several weeks or altogether if human activity continues.
[49] Most bat species are vulnerable to human disturbance, but attempts to view M. gigas at their roosts are especially discouraged due to the rapid decline in range and population.
The Queensland and South Australian state registers note the species as endangered and in Western Australia it is classified as vulnerable to threatening factors.
[50] Despite a well documented decline, the relevant criteria of legislation was not found to support a relisting of their status as endangered without analysis of genetic variation in the population.