Common Big-eared Bat

Identification

The common big-eared bat is a small species, weighing just 3.4–9.1 grams, with a forearm length of 32–38 mm. Its most distinctive feature is its large, rounded ears, measuring 18–23 mm long and connected by an inter-auricular membrane that spans between them. The bat's fur is brown, though the exact shade varies depending on geographic location. Like all members of the Phyllostomidae family, it possesses a characteristic leaf-nose formation used in echolocation.

Range & Habitat

This species is found across a wide range of South and Central America, occurring in Belize, Bolivia, Brazil, Colombia, Costa Rica, El Salvador, French Guiana, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, and Venezuela. Its broad distribution suggests it is adaptable to various tropical and subtropical habitats throughout the region.

Behaviour & Diet

The common big-eared bat possesses a remarkable and unique echolocation ability that sets it apart from most other bat species. While most echolocating bats detect prey by tracking movement—identifying glints or Doppler shifts caused by wingbeats—M. microtis can locate completely motionless prey within dense, cluttered environments. This extraordinary skill allows it to hunt with precision in extremely complex sonic landscapes where visual and acoustic clutter would overwhelm other species.

The bat's echolocation call is a broad-band multi-harmonic frequency-modulated sweep, with most energy concentrated in the second harmonic between 75 and 95 kHz. This call structure is similar to that of the long-legged bat (Macrophyllum macrophyllum), though presumably of lower intensity. Like all Phyllostomidae members, it emits its echolocation calls through its nostrils rather than its mouth. Maternal care is notably extended in this species: mothers continue to provide their pups with prey items for up to five months after weaning, suggesting complex learning of foraging techniques.

Best Time & Places to See It

The common big-eared bat's wide distribution across Central and South America means it may be encountered in suitable habitats throughout its range, from Mexico to Venezuela and Brazil. However, specific seasonal patterns and preferred microhabitats within this range are not well documented. Travellers exploring tropical forests, caves, and woodland areas in any of the thirteen countries where it occurs may encounter this species, particularly during evening foraging hours.

Photography Tips

Photographing this tiny bat presents significant challenges due to its small size and nocturnal habits. Night-vision or infrared photography equipment will be essential for capturing images in the field. The bat's large, distinctive ears and leaf-nose formation are key identifying features worth highlighting in photographs. Given the species' small size and preference for cluttered forest environments, patience and specialized macro photography techniques will yield the best results.