This bat is broadly distributed across the lowland rainforest and savanna zones of Africa from Senegal in the west, through to South Africa in the south and Ethiopia in the east (possibly ranging into Djibouti and southern Eritrea). It is also present on the extreme southwest Arabian Peninsula, where it has been recorded from Yemen and Saudi Arabia (Harrison and Bates 1991). Populations of this bat occur on several offshore islands including the Gulf of Guinea islands and Zanzibar, Pemba and Mafia (off Tanzania) (Bergmans 1990; Simmons 2005). There is a possibly disjunct population in the Air Mountains of Niger. Distribution at northern and southern extremes of the range is patchy and erratic. It is also sparse or absent in large areas of the Horn of Africa, central East Africa, and elsewhere (Bergmans, 1990). This bat is a migratory species in parts of its range; populations migrate from the West African forest north into the savanna zone during the major wet season. It ranges from sea level to around 2,000 m asl (Ruwenzori Mountains).

Eidolon helvum is the most widely distributed African fruit bat. It occurs in most of the subsaharan African continent in forest and savannah zones, the southwestern Arabian penninsula, and Madagascar. A good portion of southern Africa south of Zambia, Malawi, and Mozambique is used for migration purposes.

Biogeographic Regions: ethiopian (Native )

E. helvum is not entirely straw-colored as its common name would suggest. The neck and back display this signature color while the ventral side of the body is a duller color of brown or grey.

This is one of the larger species of fruit bats. The males are slightly larger than the females. The head and body length is reported to be between 143 and 215 mm. Weights range between 230 and 350 g.

The wings are large and narrow, allowing the bat to fly long distances and not expend as much energy trying to flap them a lot. The wingspan can reach as much as 762 mm.

The head is large and pointed with large eyes and no white facial markings. (Happold, 1987)

Range mass: 230 to 350 g.

Range length: 143 to 215 mm.

Range wingspan: 762 (high) mm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: male larger

Habitat and Ecology

Systems

• Terrestrial

These bats occupy a wide range of habitats, from coastal forests to dry, arid regions are used during the year. Prime habitat is tropical forests because of the abundance of food. Straw-colored fruit bats are found at elevations from sea level to 2000 m. These animals typically roost in tall trees, but have also been found in caves. There is great interaction with human communities as well.

Range elevation: sea level to 2000 m.

Habitat Regions: temperate ; tropical ; terrestrial

Terrestrial Biomes: savanna or grassland ; forest ; rainforest

Other Habitat Features: urban ; suburban ; agricultural

E. helvum is frugivorous. Food is can be consumed while hanging by the phalanges of the feet. The food is eaten noisily. The juices are ingested and the fibrous material is discarded. In addition to consuming fruit juices, these animals are reported to chew up wood and bark, apparently to obtain moisture.

Foods eaten include: Borassus spp., dates, baobab flowers, Adansonia digitata, Bombax spp., Erythrina spp., mangoes, pawpaws, avocado pears, figs, passion fruit, custard apples and loquats.

Plant Foods: wood, bark, or stems; fruit

Primary Diet: herbivore (Folivore , Frugivore )

Because these bats visit flowers, they play a role in pollination. They also serve as agents in seed dispersal.

Ecosystem Impact: disperses seeds; pollinates

Little information is available on species which prey upon these bats. Suspected predators include owls, eagles, snakes, buzzards, and civets. Humans are know to consume E. helvum in Zaire and West Africa.

Known Predators:

• humans (Homo sapiens)
• flies (Cyclopodia greefi)
• owls (Strigiformes)
• eagles (Accipitridae)
• buzzards (Accipitridae)
• snakes (Serpentes)
• civets (Viverridae)

Eidolon helvum is prey of:
Strigiformes
Serpentes
Accipitridae
Buteo
Homo sapiens
Viverridae

This list may not be complete but is based on published studies.

Little information on communication in this species could be found. However, these animals are reported to be quite noisy. In addition to being loud eaters, they apparently chatter to one another in their roosts, indicating that some form of acoustic commmunication is employed. Because they roost in such large groups, it is likely that individuals come into physical contact frequently, and so probably use some sort of tactile communication as well.

Communication Channels: tactile ; acoustic

Perception Channels: visual ; acoustic

The young are the result of delayed implantation. The embryonic development is 4 months before partrution with a birth weight of 45-50 grams. (Nowak, 1997)

Fifteen years is the expected life span of E. helvum. Some individuals do make it to their early twenties, and one individual is reported to have reached 21 years and ten months of age.

Range lifespan

Status: captivity: 22 (high) years.

Average lifespan

Status: wild: 15 years.

Average lifespan

Status: captivity: 21.8 years.

Maximum longevity: 21.8 years (captivity) Observations: Although the gestation period takes at least 9 months, the embryonic development is completed in 4 months (Ronald Nowak 1999).

Information on the mating system of these animals is lacking.

Mating occurs in colonies from April to June. The reproductive cycle responds to rainfall, and allows weaning of young to proceed at the time of greatest food availability.

Pairs breed when the dry season begins. There is a delay in the implantation of the embryo in most, but not all, populations. The gestation period typically lasts 9 months, but the embryo only takes 4 months to develop. In populations without delayed implantation, births occur just 4 months after mating.

The young are born in February and March. Females give birth to a single offspring that weighs 50 grams at birth.

Breeding interval: These animals breed annually.

Breeding season: These bats breed from April to June

Range number of offspring: 1 to 2.

Average number of offspring: 1.

Average gestation period: 9 months.

Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); fertilization (Internal ); viviparous ; delayed implantation

Average birth mass: 50 g.

Average gestation period: 275 days.

Average number of offspring: 1.

The straw-colored fruit bat has female parental care, like all other mammals. The female nurses her offspring until it is ready to forage on its own. In this species, young are not able to fly at birth,and so are considered altricial. Although females give birth to their young in large colonies, there are no reports of cooperative care of young, nor of paternal involvement in care of offspring.

Parental Investment: altricial ; pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female)

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Species: 22
Species With Barcodes: 1

This is a very abundant and common species that has no legal protection.

US Migratory Bird Act: no special status

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: near threatened

Population

Population Trend

Major Threats

Conservation Actions

Agriculture is greatly affected by E. helvum because these bats live in large colonies that roost near their food source. They can feed heavily in plantations. It is difficult to assess the relative utility of the species as a polinator, versus its negative impact as a crop pest.

Negative Impacts: crop pest

E. helvum are an important diet item for humans in some areas. Straw-colored fruit bats are also important pollinating agents for economically important trees in families Moracea and Bombacear.

Positive Impacts: food ; pollinates crops