Rhinolophus megaphyllus
smaller horseshoe bat

Rhinolophus megaphyllus (smaller horseshoe bat or eastern horseshoe bat) is found in a large part of the Oriental biogeographic region and the eastern Australian region. Its distribution is throughout Thailand, Malaysia, Moluccas, New Guinea, the Lesser Sunda Islands, and the east coast of Australia. Accounts suggest that smaller horseshoe bats are found in the eastern portion of New Guinea. (Flannery, 1995; Grzimek, et al., 2003)

Smaller horseshoe bats are found in temperate and tropical rainforests, deciduous forest, sclerophyll forest, woodlands, coastal scrub, and grasslands. They roost in caves, mines, rock outcrops, and non-occupied buildings. Smaller horseshoe bats can be seen forming colonies in abandoned bunkers. During the breeding season colonies are usually small, having less than twenty bats. However, outside of the breeding season, colonies consist of two thousand individuals. Those bats that occupy temperate regions become torpid during winter months and form single roosts. Tropical areas are occupied year round the bats remain active. ("Australian Museum Online", 2007; Grzimek, et al., 2003; Strahan, 1995)

Individuals have gray brown fur, with the abdominal fur being lighter than the rest. The lower portion of the nose is shaped like a horseshoe and there is a pointed nasal appendage on above the nose. There is a rufous form of smaller horseshoe bats that occurs in Queensland, Australia. These individuals tend to have more grey fur, as opposed to the standard brown. They are unique from the rest due to their fur, which changes color with age and sex. ("Australian Museum Online", 2007; Flannery, 1995; Grzimek, et al., 2003; Menkorst, 1995; Nowak, 1994; Strahan, 1995; Taylor, 1984)

One account of copulation places the incident during midday, in a cave; both individuals were hanging upside down by their toes. Smaller horseshoe bats are thought to be a polygynous species. (Grzimek, et al., 2003; Strahan, 1995)

Males produce sperm starting, approximately, in February and continuing through March. In the latter part of June copulation, ovulation, and fertilization occur. Gestation has a duration of approximately four months. Births occur from late October through November. The offspring are nursed for two months. During pregnancy females form maternity colonies that may have as few as fifteen individuals or as many as two thousand. This formation occurs during the spring and summer seasons, with choice roosting being in humid caves. The conditions of the cave are thought to increase the metabolic rate of individuals and ensure quick development of young. Maternity colonies created by females are distinct from winter roosts. There may only be a few males present, whereas the winter roosts are inhabited by males continuously. Males reach sexual maturity in the second to third year of life; females reach sexual maturity in their third year of life, sometimes the latter part of their second. (Grzimek, et al., 2003; Menkorst, 1995; Pavey, 1998; Strahan, 1995)

Like other bat species, smaller horseshoe bat females care for their young until they can fly and find food on their own. Females invest heavily in young during gestation and lactation and young are adult sized within a few months of birth.

There is no information on the longevity of smaller horseshoe bats.

Rhinolophus megaphyllus is thought to select roosts based on high humidity and relatively warm temperatures. Complete darkness does not appear to be a requirement. The high humidity of roost caves is thought to help keep bats from needing as much water, especially during times of inactivity. Roosts used for communal, year round living by the colony, are found in a variety of different locations. Caves are the top choice, however rock outcrops, abandoned buildings and bunkers are also used. Maternity colonies only occur in caves. (Grzimek, et al., 2003; Menkorst, 1995; Strahan, 1995)

Home ranges are not documented for smaller horseshoe bats.

Members of Rhinolophus megaphyllus navigate and find food through the use of echolocation. They use constant frequency calls of 67 to 71 kHz. Individuals communicate through audible vocalizations and chemical cues. These bats also have keen vision. (Pavey and Burwell, 2005)

Smaller horseshoe bats are insectivores. They eat moths, other flying insects, and spiders. The prey they prefer are moths, specifically Speiredonia spectans and Speiredonia mutabilis. They obtain food primarily while flying. Their flight patterns are characterized by slow, fluttering flight around dense foliage. The echolocation calls of smaller horseshoe bats occur at frequencies that permit distinguishing between flying prey and the surrounding foliage. Smaller horseshoe bats stay primarily in wooded areas. They do not forage over grasslands. Individuals also capture prey by flying out from a stationary perch to catch passing prey. ("Australian Museum Online", 2007; Grzimek, et al., 2003; Pavey and Burwell, 2005; Pavey, 1998)

There are no specific reports of predation on smaller horseshoe bats. In general, bats are preyed on by owls and other raptors in flight and by arboreal predators in their cave roosts.

Smaller horseshoe bats are important predators of insects in their native ecosystems.

Smaller horseshoe bats are important member of native ecosystems. Their predation on flying insects can impact agricultural pest populations, providing a benefit to farmers.

There are no known adverse effects of Rhinolophus megaphyllus on humans (Grzimek, et al., 2003)

The status of Rhinolophus megaphyllus on IUCN Red List is lowest risk, least concern. This species was not listed under any appendices of CITES.

In most reference books these bats are referred to as eastern horseshoe bats.