Overview
The Large-eared Giant Mastiff Bat (Otomops martiensseni) is an extraordinary, aerodynamic chiropteran celebrated for its bizarre facial morphology and exceptional high-altitude flight dynamics. Inhabiting volcanic lava tubes and vast limestone subterranean systems across eastern and southern Africa, this large molossid bat boasts colossal ears that unite over the bridge of its snout, creating a natural acoustic horn. Acting as an aerial apex predator of the night skies, it hunts evasive nocturnal insects hundreds of meters above the ground, filling a vital ecological role across African savanna biomes.
Biology and Physical Characteristics
Otomops martiensseni displays striking velvety dark-brown to black pelage bordered by a conspicuous pale grey or cream collar across its shoulders. Its most jaw-dropping anatomical feature is its oversized, forward-facing ears, which span almost 40 millimeters and are joined centrally above the rostrum by a fleshy membrane flap, functioning to reduce aerodynamic drag during high-speed flight. The bat features long, narrow wings engineered with high wing loading and high aspect ratio, built for rapid, sustained flight rather than slow, cluttered navigation.
Behavior and Ecology
Unlike many forest-dwelling bats that maneuver through dense branches, the large-eared giant mastiff bat is a specialized open-air hawker. Colonies emerge late at night from deep subterranean roosts, rocketing high into the open troposphere at speeds exceeding 40 mph (65 km/h). They employ low-frequency, narrow-band echolocation pulses (typically around 15–20 kHz), which carry over immense distances and fall below the hearing threshold of tympanate moths, allowing the bat to ambush evasive prey before they can evade.
Conservation and Human Impact
Currently listed as Near Threatened by the IUCN, Otomops martiensseni faces substantial threats arising from its extreme dependence on a tiny number of massive subterranean roosting sites. Heavy disturbance from commercial guano harvesting, cave tourism, smoke from agricultural fires, and the destruction of cave mouths for mining have led to the catastrophic abandonment of several historic maternity colonies, including in the iconic lava tubes of Mount Suswa in Kenya.
Interesting Factoid
The huge ears of the Large-eared Giant Mastiff Bat are literally connected together across the top of its head, turning its face into a biological radar dish that detects ultrasonic echoes from flying moths nearly a football field away!
Last updated: October 2026