Overview
The Reunion Free-tailed Bat (Mormopterus francoismoutoui) is a small, agile molossid bat endemic to the rugged volcanic island of Réunion in the southwestern Indian Ocean. Recognized as a distinct species in 2008 following comprehensive genetic analysis, this tireless nocturnal insect-hunter occupies a vital ecological role as the primary mammalian regulator of insect populations across the island’s diverse ecological zones.
Biology and Physical Characteristics
Mormopterus francoismoutoui is characterized by sleek, dark chocolate-brown to grey-brown velvety pelage, a robust wrinkled snout, and relatively broad ears separated along the forehead. As a typical free-tailed bat, the terminal half of its muscular tail projects freely beyond the posterior margin of the interfemoral membrane (uropatagium). Its long, narrow, high-aspect-ratio wings are engineered for rapid, energy-efficient high-altitude cruising in open skies rather than fluttering maneuverability in dense understory brush.
Behavior and Ecology
Emerging from roosts in synchronized waves at dusk, Reunion Free-tailed Bats forage over open ocean shores, sugarcane plantations, highland volcanic peaks, and urban gardens up to 2,000 meters in elevation. Utilizing powerful, low-frequency frequency-modulated echolocation calls, they detect aerial swarms of moths, mosquitoes, and beetles at long range, diving at steep angles to scoop up prey in their wing membranes. They roost colonially in massive basalt sea-caves, volcanic lava tubes, rock crevices, and beneath corrugated roof eaves.
Conservation and Human Impact
Evaluated as Least Concern by the IUCN, the Reunion Free-tailed Bat is abundant across Réunion, with total population estimates exceeding several hundred thousand individuals. Because colonies frequently congregate in domestic attics and public buildings, local conservation organizations conduct public outreach to protect colonies from pesticide poisoning, exclusion, and harassment, promoting bat-friendly construction designs and artificial bat houses.
Interesting Factoid
The Reunion Free-tailed Bat is one of only two bat species native to the volcanic island of Réunion, consuming up to one-third of its body weight in night-flying mosquitoes and agricultural moths every single evening.
Last updated: October 2026