Nycteris grandis

Geographic Range

Large slit-faced bats are native to central and southern Africa.

• Biogeographic Regions
• ethiopian ethiopian
  • native native

Habitat

Large slit-faced bats are most commonly found in swampy sites in rainforests. They make their roosts in hollow trees, small caverns in rocks, hollow fallen logs, and manmade structures. Large slit-faced bats are also found in dry savannah habitats.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial

• Terrestrial Biomes
• savanna or grassland savanna or grassland
• forest forest
• rainforest rainforest

• Wetlands
• swamp swamp

• Other Habitat Features
• suburban suburban
• agricultural agricultural

Physical Description

Large slit-faced bats are large bats that have reddish brown to gray fur on the top part of their body and paler and grayer fur on the underside. A female found in Zambia had a slight yellow tinge around its neck and shoulders. The face has a deep frontal groove that houses the noseleave and extends from the nostrils to a line joining the base of the ears. This groove is surrounded by fleshy lobes and flanges. Large slit-faced bats are not sexually dimorphic in size. Their tails range in length from 65 to 75mm and terminate in a Y or T shaped piece of cartilage. Their body and head length ranges from 63-93 mm and their body mass is from 23 to 36 g, which makes them the largest member of the family Nycteridae . They have large ears, ranging from 28 to 35 mm; this can be as much as 50% of their forearm length. The forearms range from 57 to 66 mm, and their tibias range in length from 29.5 to 33.5 mm.

Large slit-faced bats have trifid incisors, that is, their incisors are divided into three narrow parts or lobes. A few dimensions of their skulls are as follows: length of skull, 26-27 mm, breadth of zygomatic arch, 16-17 mm, length of maxillary tooth row, 9.1-9.7 mm and width of the maxillary 10.4-11.1 mm.

Member of the family Nycteridae can be distinguished from all other bats by their tails ending in a Y or T shaped piece of cartilage. Large slit-faced bats can be distinguished from all other Nycteridae except Nycteris hispida by their trifid upper incisors. They can be distinguished from Nycteris hispida by the larger size and forearm length of N. grandis . Large slit-faced bats have skin temperatures that range from 33.5 to 38.0°C.

• Other Physical Features
• endothermic endothermic
• heterothermic heterothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike

Reproduction

Little is known about the reproductive and mating habits of large slit-faced bats. It is likely that these bats are monogamous because pairing and roost fidelity is quite common in this species.

• Mating System
• monogamous monogamous

Little is known about the reproduction and development of large slit-faced bats. One offspring is born to a female per breeding season. It is possible that there are two breeding seasons, but this is uncertain. In one study in Zimbabwe in December, some female large slit-faced bats were found with offspring that were 1-7 days old. In Liberia, a female was found in December with a 5 mm embryo. Another study collected 7 females in September in Zambia; these had single fetuses with crown-rump lengths of 24-27 mm and head lengths of 17-18 mm. The amount of time to weaning and the age at which the offspring reaches sexual maturity is unknown. In related bats such as Nycteris hispida and Nycteris thebaica adult size is reached in about two months, and females continue to nurse their offspring from 45 to 60 days.

It has been documented that females and their young can recognize each other. In several cases, when a female returned to a roost after foraging, her offspring recognized her and began to rapidly flap its wings.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
• viviparous viviparous

Not much is known about parental investment in large slit-faced bats. Females nurse their young in day roosts and leave them when they forage for food. They are similar to other mammals in that the mother cares for her young until it is ready for independence. The role of male large slit-faced bats in raising offspring is unknown.

• Parental Investment
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female

Lifespan/Longevity

There is no information on the lifespan or longevity of this species. Large slit-faced bats most likely live for many years since most microchiropterans are fairly long lived.

Behavior

Nycteris grandis can be found roosting alone, in pairs, or in small groups. These bats show high levels of roost fidelity; that is, they return to the same roost each day. Large slit-faced bats use a variety of different roosts for day roosts, feeding roosts, and night roosts. Females pass the day and nurse their young in day roosts. Night roosts are used as hunting perches. Nycteris grandis individuals take prey that they have caught to a feeding roost, which is usually within 20 m of their day roost. This may be a strategy to avoid having their prey stolen by other bats in the day roosts.

After feedilng, these bats usually groom themselves before approaching other Nycteris grandis .

Migratory patterns in Nycteris grandis have not been observed, however the related bat Nycteris thebaica has been known to migrate. There is little information about why this occurs in Nycteris thebiaca and it has been hypothesized that migration occurs as a result of resource availability.

• Key Behaviors
• flies
• nocturnal nocturnal
• motile motile
• sedentary sedentary
• daily torpor
• social social

Home Range

There is no information about the home range of this species.

Communication and Perception

Like many other bats, Nycteris grandis uses echolocation. During attacks Nycteris grandis produces echolocation calls, increasing the rate of calling as it approaches its prey. The spectra of calls early in the feeding sequence have four peaks (20-112 kHz), and the calls later in the approach have a single peak at approximately 73-91 kHz. The minimum and maximum frequencies of the early calls in the approach are 17 and 114 kHz and for the later calls are 61 and 110 kHz. The pulse duration varies from 0.6 to 2.8 ms and the interpulse interval varies from 6.0 to 17.8 ms. Nycteris grandis emits echolocation calls through their nostrils, and their noseleaf may play a role in ampilyfing the sound. Large slit-faced bats also use other modes of perception to locate and capture prey, including passive hearing and vision. The large ears of Nycteris grandis have their higest sensitivity between 10 and 20 kHz, a frequency used to detect sounds made by prey.

Interspecific communication has not been widely studied in bats, but it is likely that large slit-faced bats use chemical and auditory cues, as well as tactile and visual cues, to communicate among individuals.

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• ultrasound ultrasound
• echolocation echolocation
• chemical chemical

Food Habits

Large slit-faced bats are opportunistic foragers that use two foraging strategies and eats a broad range of prey. Large slit-faced bats eat arthropods, bats, frogs, fish and birds. Their diets vary based on the season, with frogs being the most common prey in March, April, May, August, and September. Other bats are common prey in June and July, and arthropods are most common in December, January, and February. For large prey like bats and birds, Nycteris grandis grasp them in their mouths and immobilize them with a strong bite to the head.

Large slit-faced bats use two foraging strategies. The most common strategy involves hunting from a perch where the bats wait for prey to pass by. They then use short flights to attack the prey on the ground where they envelop it with their wings. They also take longer flights in search of food on the ground or in the air. They switch between each type of foraging strategy based on habitat and prey availability. Large slit-faced bats hunt at night from night roosts. They use prey-generated sounds to locate their targets, which explains why noisy prey are their most common targets.

Some of the common arthropods eaten by large slit-faced bats are crickets , moths , cicadas , hydrophilid beetles and katydids . The diet is influenced by prey availability and results in these bats choosing a variety of prey. These bats can take large prey, up to 33% of their body mass.

Large slit-faced bats consume their prey while hanging from a perch with one foot. They use their wings to hold and position the prey. The discarded prey remains, such as skin, fur, and wings, fall to the ground beneath their feeding roosts, making these roosts easily recognized by researchers.

• Primary Diet
• carnivore carnivore
  • eats terrestrial vertebrates
  • insectivore insectivore

• Animal Foods
• birds
• mammals
• amphibians
• reptiles
• fish
• insects

Predation

Little is known about the predators of Nycteris grandis . The most common predators of bats in the genus Nycteris are snakes and large birds of prey , for example bat hawks . Possibily to avoid predators, these bats roost in high places where it is hard for predators to get to them.

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

Nycteris grandis has a large impact on many different species in their ecosystem because they eat such a wide variety of foods. Like many bats, Nycteris grandis eats large amounts of insects which likely affects the populations of those species. They also feed on vertebrates, including other bats. Large slit-faced bats are hosts to parasites called broad trypanosomes, but there is little information available about this relationship.

Economic Importance for Humans: Positive

These bats eat insects, helping to control pest populations.

• Positive Impacts
• controls pest population

Economic Importance for Humans: Negative

There are no known adverse effects of Nycteris grandis on humans.

Conservation Status

Large slit-faced bat populations are not currently considered threatened.

Other Comments

Nycteris is derived from the Greek word nykteros , which means "nocturnal". The name grandis is derived from the Latin word grandis , which means "magnificent".

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Jim Aldrich (author), University of Michigan-Ann Arbor, Phil Myers (editor, instructor), Museum of Zoology, University of Michigan-Ann Arbor.

References

Bayefsky-Anand, S. 2005. Effect of location and season on the arthropod prey of Nycteris grandis. African Zoology , 40: 93-97.

Esmailka, L., L. Olson. 2005. "Animal Diversity Web" (On-line). Accessed March 20, 2006 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Nycteris_thebaica.html#a78781892edb4c5e83de7199c60849ea .

Fenton, M., D. Cumming, J. Hutton, C. Swanepoel. 1987. Foraging and habitat use by Nycteris grandis in Zimbabwe. Journal of Zoology , 211: 709-716.

Hickey, M., J. Dunlop. 2000. Nycteris Grandis. Mammalian Species , 632: 1-4.

Parey, V., H. Berlin. 1993. Variation in foraging behaviour, habitat use and diet of Large slit-facebats (Nycteris grandis). Zeitschrift fur Saugetierkunde , 58: 65-74.

Park, A., P. Myers. 2004. "Animal Diversity Web" (On-line). Accessed March 20, 2006 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Nycteris_hispida.html .

2006. "Regions Containing Large Slit Faced Bats" (On-line). Wild Finder. Accessed February 24, 2006 at http://www.worldwildlife.org/wildfinder/searchBySpecies.cfm?speciesID=13756 .