Rhinolophus hipposideros
lesser horseshoe bat

The distribution of lesser horseshoe bats, Rhinolophus hipposideros, ranges from the western part of Europe to central Asia and from central Europe down to the northern part of Africa. Although they are widespread throughout their range, they are a rare species, and populations have declined in the northern parts of the range. They have become extinct in the southeastern part of Britain, and in Britain are now restricted to southwest England and Wales. ("UK Biodiversity Action Plan", 2006; Schober and Grimmberger, 1989; Stebbings and Griffith, 1986)

Lesser horseshoe bats prefer shrubland, valleys, and open grassland and woodland edges. They naturally roost in caves, but with the spread of the human population into their habitats, they have found homes in man-made structures, including roofs, tunnels, attics, and cellars. Because of their small size, they have an advantage over larger bats for access to small crevices and openings as roosting sites. In the summer, lesser horseshoe bats of the north roost in warm attics or heated basements. In the south, they roost in caves and tunnels. Lesser horseshoe bats hibernate from October until late April or early May, most often in caves, tunnels, and cellars. Roosting individuals prefer to hang in close proximity to others when hibernating. Summer and winter roosts are usually no more than 5-10 km apart. ("UK Biodiversity Action Plan", 2006; Schober and Grimmberger, 1997; Walker, 2005)

Lesser horseshoe bats are the smallest of the European horseshoe bats, approximately the size of a person’s thumb. They are slightly smaller than their close relative, greater horseshoe bats, Rhinolophus ferrumequinum, weighing only 5-9 grams. They have a wingspan of 192 to 254 mm. Their body length is usually 35 to 45 mm and tail length is 23 to 33 mm. Like all other bats in the family Rhinolophidae, lesser horseshoe bats have leaf-like projections on their noses that aid in echolocation, and the species takes its name from their horseshoe-shaped nose. They have pointed ears without a tragus. Their legs are long and slender with strong feet to help hold onto branches and cave walls. The fur is brown on the back, while the underside is a whitish gray color. The wings, relatively broad and somewhat rounded, allow maneuverability while flying in dense vegetation. The ears and wing membranes are a grayish brown color and, when roosting, these bats wrap themselves completely inside their wings. Young lesser horseshoe bats are quite distinctive from adults because all of the fur on their body is gray. ("UK Biodiversity Action Plan", 2006; Altringham, 1999; Schober and Grimmberger, 1989; Walker, 2005)

The mating system of lesser horseshoe bats is not well known. They breed in the autumn. There have been observations of courtship, in which a male and female chase each other around before settling down to mate. (Schober and Grimmberger, 1989)

Lesser horseshoe bats reach sexual maturity at about one year old. Mating occurs in the autum, and about one-half to two-thirds of females give birth to one young. The rest give birth to twins. In early April, females and some males (about 20%) form maternity roosts with group sizes ranging from 10 to 100 individuals. These roosts may be shared with bats of other species, including greater mouse-eared bats, Myotis myotis, and Geoffroy’s bats, Myotis emarginatus, but the species do not roost in the same parts of the roost structure. Young are born in mid June to early July and weigh about 1.8 grams. They are covered in fine, gray hairs except on the underside, and have sensitive hairs near the noseleaf. Their eyes open at about 10 days. They are weaned at 4 weeks and become independent at 6 to 7 weeks. Individuals in maternity roosts separate in August. (Altringham, 1999; Schober and Grimmberger, 1997; Walker, 2005)

Little information is available about the parental investment of lesser horseshoe bats. Females do most of the caring of the young and, although maternity roosts may consist of many individuals, females keep to themselves and do not help each other in caring for young. Young bats tend to develop quickly and reach independence soon after weaning. (Schober and Grimmberger, 1989)

Not much information has been recorded about the lifespans of these animals in the wild or in captivity. In the wild, the average lifespan is about 3 to 4 years. The maximum age recorded in captivity is 21 years. (Schober and Grimmberger, 1997)

Lesser horseshoe bats are solitary except when forming maternity (breeding) roosts in the summer. During this time, groups of 10 to 100 individuals, consisting of mostly females, come together to raise young. When hibernating in the winter, these bats prefer to roost individually, but in close proximity to others. ("UK Biodiversity Action Plan", 2006; Csorba, et al., 2003; Schober and Grimmberger, 1997; Walker, 2005)

Lesser horseshoe bats do not migrate and only travel 5 to 10 km between summer and winter roosts. The longest distance recorded traveled by a lesser horseshoe bat is 153 km. (Schober and Grimmberger, 1997)

Echolocation is the primary means by which these bats capture prey. Calls range from 105 to 111 kHz, ending in a short drop in frequency. The duration is about 20 to 30 ms. The calls of lesser horseshoe bats sound much like a chirp, and overlap in characteristics with other species of bat, specifically Mediterranean horseshoe bats, Rhinolophus euryale, and Mehely’s horseshoe bats, Rhinolophus mehelyi. There are also small differences in frequency within Rhinolophus hipposideros depending on geographic location. (Schober and Grimmberger, 1997)

Lesser horseshoe bats prey mainly on small insects, such as mosquitoes, crane flies, and beetles. They use their high frequency echolocation calls to detect prey. Along with their maneuverable wings, agility, and speed, they are formidable predators in forested areas. Compared to the greater horseshoe bat, Rhinolophus ferrumequinum, the lesser horseshoe bat spends a relatively longer time foraging. They move in a whirling fashion and tend to stay close to the ground, up to 5 m high. They have a fluttering flight, with relatively fast wing beats, and can hover in one spot. Most of the time, they snatch prey in mid-air, but can take up insects from branches, rocks, and bushes. (Arlettaz, et al., 2000; McAney and Fairly, 1989; Schober and Grimmberger, 1989)

The main diet of lesser horseshoe bats consists of insects from 23 families and 7 orders (Lepidoptera, Neuroptera, Trichoptera, Hymenoptera, Coleoptera, Diptera, and Hemiptera). During April to September, Lepidoptera, Diptera, and Neuroptera are the main families consumed. They also eat spiders (Arachnida). Lesser horseshoe bats usually hunt near water and damp wooded areas and catch prey by hawking, snatching them from mid-air, grabbing them from branches and rocks, and pouncing on them near the ground. (Arlettaz, et al., 2000; McAney and Fairly, 1989; Schober and Grimmberger, 1989)

Lesser horseshoe bats are vulnerable to terrestrial as well as aerial predators. They have a wide variety of avian predators including hawks, owls, and other large birds. On the ground, they are preyed upon by other mammals such as European pine martens (Martes martes), and domestic cats.

Echolocating bats are probably more vunerable to aerial predation than small insectivorous birds because most bats are relatively slow fliers and rely on echolocation rather than on vision. (Jones and Rydell, 1994; Presetnik, 2004)

Lesser horseshoe bats impact their ecosystem by feeding on large numbers of insects. ("UK Biodiversity Action Plan", 2006)

Lesser horseshoe bats help reduce insect pest populations. ("UK Biodiversity Action Plan", 2006)

All bats are known to carry the rabies virus. Because bats are losing their habitat to human development and expansion, they are moving closer and closer to human populated areas. Even though accounts of bats transmitting rabies to humans are uncommon, the risk is present and caution must be taken when in contact with these creatures.

Because lesser horseshoe bats occupy many human dwellings when they roost, including cellars and attics, they are sometimes regarded as unwelcome pests. However, preventative measures can be taken to keep these bats from entering houses, such as blocking any crevices or holes in the walls through which these bats may crawl. ("UK Biodiversity Action Plan", 2006; "UNEP World Conservation Monitoring Centre", 2006)

The IUCN has listed the current conservation status of lesser horseshoe bats as vulnerable, which means that they do not face extinction in the wild at the present time, but may face the risk of becoming vulnerable to extinction in the near future. The major threats to their population are habitat loss due to human disturbance, pollution, and a change in prey dynamics due to human disturbance. ("2004 IUCN Red List of Threatened Species", 2006)