Overview
The Bristle-faced Free-tailed Bat (Mormopterus eleryi) is one of Australia’s rarest, most secretive, and ecologically specialized microbats. First formally identified and separated from regional species complexes in 2008, this diminutive molossid bat navigates the vast, dry mulga and acacia woodlands of the Australian arid zone. Instantly distinguished by an unusual cluster of elongated, tactile sensory bristles surrounding its upper muzzle, it roosts in tiny tree hollows and commands night skies as an agile aerial predator of arid insects.
Biology and Physical Characteristics
Mormopterus eleryi possesses several morphological specializations that set it apart from other Australian free-tailed bats. Its most striking physical attribute is a dense moustache of stiff, prominent hair-like bristles sprouting around the upper lip and snout, which function as tactile mechanoreceptors to detect branches and obstacles in confined roosting hollows. Clothed in soft, sandy-brown to greyish fur, it features a characteristic free tail that extends noticeably beyond the narrow uropatagium membrane. Its long, narrow wings are engineered for rapid, high-speed flight across open woodland clearings.
Behavior and Ecology
Operating as a strictly nocturnal forager, the bristle-faced free-tailed bat emerges at dusk from hollow trunks of mature river red gums, coolibahs, and desert bloodwoods. Utilizing low-frequency, high-intensity echolocation calls tuned between 25 and 32 kHz, it targets flying insects above tree canopies and along arid watercourse corridors. The bat is exceptionally dependent on old-growth hollow-bearing trees; maternity colonies composed of several dozen females congregate in narrow, insulated limb cracks during late spring to birth and rear single pups.
Conservation and Human Impact
The bristle-faced free-tailed bat is listed as Endangered under Australian conservation legislation due to its tiny, fragmented population and the severe loss of ancient hollow-bearing trees across its range. Intensive land clearing for pastoral grazing, extensive wildfires fueled by invasive buffelgrass, and firewood collection have decimated natural roosting hollows that take over a century to form. Conserving mature desert woodland corridors and protecting remnant eucalyptus stands along dry watercourses remain essential priorities.
Interesting Factoid
Unlike most bats that navigate tight spaces using echolocation alone, the Bristle-faced Free-tailed Bat relies on a dense halo of stiff facial whiskers—similar to a rodent’s whiskers—to squeeze safely into tiny, pitch-black tree fissures.
Last updated: October 2026