Cynopterus horsfieldii

Geographic Range

Horsfield's fruit bats ( Cynopterus horsfieldii ) are found throughout peninsular Malaysia, Cambodia, southern Thailand and several islands in the Malay Archipelago including the Greater Sunda Islands (Sumatra, Java and Borneo) and the Lesser Sunda Islands (Lombok and Sumbawa).

• Biogeographic Regions
• oriental oriental
  • native native

Habitat

Horsfield's fruit bats can be found in several differing habitats ranging from primary and secondary forests, rainforests, agricultural lands, parks, mangroves, limestone caves and gardens. They are commonly found within ecotonal areas, the transitional areas between forests and cultivated land. A study in Malaysia looked at the vertical stratification of fruit bats based on wing morphology, Horsfield's fruit bats were commonly captured in mist nets from 1 to 28 m. Researchers in this study predicted that Horsfield's fruit bats are more prevalent in the mid-storey airspace, which is classified as 10 to 20 m from the forest floor. A comparative study of roosting ecology found that Horsfield's fruit bats have the second highest roosting diversity of their genus. Their roosting sites are less than 5 m above ground and within 0.25 km of the forest. These bats are commonly found utilizing both unmodified and modified roosting sites and show no preference between the two, with harems found in both. A study examining coexistence in Malaysian fruit bats found Horsfield's fruit bats have a 71.2% habitat overlap with greater short-nosed fruit bats and 35.7% habitat overlap with lesser short-nosed fruit bats .

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest
• rainforest rainforest

• Other Habitat Features
• urban urban
• suburban suburban
• agricultural agricultural
• caves

Physical Description

Horsfield’s fruit bats, also known as larger dog-faced fruit bats or peg-toothed short-nosed fruit bats , are moderately sized, with an average mass of 57.9 g. Their larger size distinguishes them from lesser short-nosed fruit bats and greater short-nosed fruit bats . Another distinguishing characteristic of this species is the presence of peg-like cusps in their lower 3rd premolar and their 1st molar. Horsfield's fruit bats are described as having the heaviest dentition in their genus; they have 30 teeth, with a dental formula of 2/2, 1/1, 3/3, 1/2. These bats have a muzzle that is both short and broad, with tubular nostrils. They have relatively large eyes and oval shaped ears that measure 17 to 22 mm and lack a tragus. Their ears, as well as their wings, have a distinctive white colored margin. Horsfield's fruit bats also have a short tail, with lengths ranging from 7 to 16 mm. Their wings have a low aspect (6.08) and high wing loading (15.98 Nm-2) ratio. Their wingspan is 465 mm and their wing area is 36,000 mm2. Their pelage is short and varies in color from dark or light, gray or brown. A study of Malaysian pteropodid hair morphology described Horsfield's fruits bats' hair as having entire coronal scales and a discontinuous medulla. Juveniles are gray, while breeding adults have an amber colored mantle, which is more distinguishable in males. Males also tend to have darker fur on the sides of their neck and chest and brighter fur on their shoulder and throat. In terms of their size, male forearms measure about 74.3 mm and female forearms measure about 75.1 mm. Their head and body length may range from 80 to 96 mm.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes colored or patterned differently
• male more colorful

Reproduction

Horsfield’s fruit bats exhibit polygyny with a harem-based social structure. Roosts typically consist of no more than one mature male, two to three mature females and their associated offspring, this is a relatively small harem compared to other members of genus Cynopterus . Adult males tend to roost separately from females, which tend to stay closer in proximity to each other. Although the sexes separate while roosting, there is no evidence of bachelor groups. In a study exploring the relationship between roosting ecology and the degree of polygyny, Horsfield's fruit bats, along with other members of Cynopterus , did not exhibit defense of females or food resources. In terms of their roosting sites, there was little evidence of defense by males.

• Mating System
• polygynous polygynous

Horsfield’s fruit bats are seasonally polyestrous and breed asynchronously, with pregnancy peaks occurring every 4 to 6 months. Reproductive females exhibit postpartum estrous and delayed embryonic development. There is limited data available specifically for this species, however, if they exhibit similar reproductive traits to greater and lesser short-nosed fruit bats their gestation period likely ranges from 4 to 6 months, males likely reach sexual maturity in 1 to 2 years, females likely reach sexual maturity in 6 to 8 months and weaning likely occurs after 40 days. Similar to greater short-nosed fruit bats , the average birth mass of Horsfield's fruit bats may be near 11 grams; this assumption is based on their comparable adult body masses.

• Key Reproductive Features
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• viviparous viviparous
• post-partum estrous

There is limited species specific data for parental investment in Horsfield’s fruit bats. Most newborn bats are altricial at birth and in general, females provision and protect their young until independence. An important aspect of parental care during this period is the maintenance of the thermal environment. Female bats commonly carry their young while foraging until they are able to fly, which drastically increases their energy expenditure and reduces their foraging efficiency.

• Parental Investment
• altricial altricial
• female parental care female parental care
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • provisioning
    • female
  • protecting
    • female

Lifespan/Longevity

There is limited data available on the longevity of this species, but a mark-recapture study of Horsfield’s fruit bats estimated an average lifespan of at least 31 months.

Behavior

Horsfield’s fruit bats are a gregarious species with a harem-based social structure. Roosts typically consist of no more than one mature harem male, two to three mature females and their associated offspring. Roost fidelity in this species is relatively low, with males and females frequently changing roosts. Roost modification is present in Horsfield’s fruit bats, with modified roosts described as inverted v-shape tents formed from severing a leaf halfway between its base and tip. A study examining the behavioral and reproductive ecology of Horsfield’s fruit bats found that they were most active 2 to 4 hours after sunset and 3 hours prior to sunrise.

• Key Behaviors
• flies
• nocturnal nocturnal
• motile motile
• social social

Home Range

A study located in a secondary rainforest in Malaysia reported the average home range size of Horsfield’s fruit bats was 8.0 ha (n=2) in males and 5.8 ± 2.5 ha (n=4) in females. Their mean greatest distance traveled in this study was 475 ± 105 m.

Communication and Perception

Horsfield’s fruit bats rely on their eyesight to navigate through the forest at night, along with their sense of smell to detect fruit.

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

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Horsfield’s fruit bats are predominately frugivorous, but also consume leaves, flowers and pollen. A study in peninsular Malaysia showed these bats feed on the following plant species: Elaeocarpus stipularis , Pternandra echinata , Artocarpus nitidus griffithii , Ficus variegata , Ficus fistulosa , Piper aduncum , along with unidentified leaves and pollen. Horsfield’s fruit bats also feed on Payena lucida and the flowers of Parkia speciosa . Studies have noted that their diet and food preference is based on seasonal availability. During the dry season, when fruit abundance is low, these bats shift their diet to an increased utilization of pollen. Horsfield’s fruit bats have also been observed feeding on fruits from orchards and gardens. These bats have been observed removing fruit from trees and moving to a feeding roost to consume them. They extract fruit juices by pushing them against their palate with their tongue, the pulp and seeds are spit out and fall to the ground. Smaller seeds are ingested and dispersed later in their feces. Body size plays an important role in resource partitioning within their genus. For instance, Horsfield’s fruit bats have a large body size and have been documented carrying heavy figs and producing heavy regurgitated pellets. There are also descriptions of these bats becoming intoxicated and lying at the base of trees after drinking palm juice collected in pots.

• Primary Diet
• herbivore herbivore
  • folivore folivore
  • frugivore frugivore

• Plant Foods
• leaves
• fruit
• pollen
• flowers

Predation

There is limited data available on the predation of this species, but in general, fruit bats, especially those on islands, have few natural predators, limited to mammals, birds of prey and reptiles.

Ecosystem Roles

Horsfield’s fruit bats, along with other fruit bat species, play a crucial role in seed dispersal and pollination of a wide array of plant species. Their role in seed dispersal and pollination has several effects on the plant community including promoting increased biodiversity, increased germination, forest regeneration, protection from seed predators, forest gap development and alteration of successional development.

• Ecosystem Impact
• disperses seeds
• pollinates

Economic Importance for Humans: Positive

The economic importance of this species is centered on their role as a pollinator and seed disperser. Several species that are pollinated or have their seeds dispersed by these bats are used for medicine, timber or food sources, resulting in millions of dollars to local economies annually.

• Positive Impacts
• pollinates crops

Economic Importance for Humans: Negative

Although there are no reported adverse effects of Horsfield’s fruit bats on humans, due to their frugivory, they are likely a pest to commercial fruit crops.

• Negative Impacts
• crop pest

Conservation Status

According to the International Union for Conservation of Nature (IUCN), Horsfield’s fruit bats are currently listed as a species of least concern because they are widespread, there are no major threats in their range and they are not declining at a rate that warrants an elevation of their status to a more threatened level. Horsfield’s fruit bats, along with other members of their genus, tolerate human disturbances and are able to roost in urban and agricultural areas.

Additional Links

Encyclopedia of Life

Contributors

Erick Smogoleski (author), University of Wisconsin-Stevens Point, Christopher Yahnke (editor), University of Wisconsin-Stevens Point, Leila Siciliano Martina (editor), Texas State University.

References

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Campbell, P., T. Kunz. 2006. Cynopterus horsfieldii . Mammalian Species , 802: 1-5. Accessed February 24, 2013 at http://www.science.smith.edu/departments/Biology/VHAYSSEN/msi/ .

Campbell, P., N. Reid, A. Zubaid, A. Adnan, T. Kunz. 2006. Comparative Roosting Ecology of Cynopterus ( Chiroptera : Pteropodidae ) Fruit Bats in Peninsular Malaysia. Biotropica , 38/6: 725-734. Accessed February 27, 2013 at http://jstor.org/stable/30044050 .

Campbell, P., C. Schneider, A. Zubaid, A. Adnan, T. Kunz. 2007. Morphological and Ecological Correlates of Coexistence in Malaysian Fruit Bats ( Chiroptera : Pteropodidae ). Journal of Mammalogy , 88/1: 105-118.

Campbell, P. 2008. The Relationship between Roosting Ecology and Degree Polygyny in Harem-Forming Bats: Perspectives from Cynopterus . Journal of Mammalogy , 89/6: 1351-1360. Accessed February 27, 2013 at http://jstor.org/stable/30224403 .

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