Pteropus rodricensis

Geographic Range

Pteropus rodricensis , also known as Rodriguez flying foxes or Rodriguez fruit bats, lives only on the Island of Rodriguez, a part of Mauritius located in the southern Indian Ocean east of Madagascar. Rodriguez is sometimes spelled "Rodrigues" in the literature.

• Biogeographic Regions
• indian ocean
  • native native

• Other Geographic Terms
• island endemic island endemic

Habitat

Due to the destruction of much of the natural environment of Rodriguez, Rodriguez flying foxes are confined to Cascade Pigeon, a small wooded valley on the island. These bats depend on dense rainforest habitat and roost in mature trees. These trees protect the bats from frequent cyclones.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest

Physical Description

Pteropus rodricensis has thick fur and is usually a dark chestnut brown color with a layer of golden-brown covering the head, neck, and shoulders. It is often called a “Golden Bat;" however, its color can also vary between black, silver, yellow-orange, and red. The body is from 15 to 20 cm long, and the wingspan from 50 to 90 cm. Individuals weigh between 300 and 350 g. There is no tail.

Rodriguez flying foxes have large eyes and large, widely spaced ears. Each thumb and second finger has a claw, and the claw on the thumb is hooked for climbing. Males and females look the same, although males are generally larger.

The basal metabolic rate of these animals is reported at 134.9 cubic cm of oxygen per hour.

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

• Sexual Dimorphism
• sexes alike
• male larger

Reproduction

In general, mating for Rodriguez flying foxes is random and promiscuous. They form harems of one male and up to 8 females. Males attract and retain females using vocal and flight displays; these are also ways that males defend their territory, which they scent-mark by rubbing their head, neck, and chest on branches. Rodriguez fruit bats are very social animals; however, males tend to roost alone, whereas females of different harems may roost together in large colonies.

• Mating System
• polygynous polygynous

In the wild, Rodriguez flying foxes breed from October to December. Females produce only one offspring per breeding season. In captivity, however, breeding occurs throughout the year and a female can produce up to two offspring per year.

Gestation lasts from 120 to 180 days. Newborns typically weigh around 20 to 30% of the mother's weight. It usually takes the female about 40 minutes to give birth. In order to give birth, she hangs right-side up from her thumbs and catches the baby with the patagium of her wings.

It is believed that females give birth alone. However, an assisted birth in captivity has been observed. The female in labor was struggling to give birth and was in the wrong position; instead of being right-side up, she was in roosting position. Another female "tutored" the mother, showing her the proper birthing position, and helped stimulate birth by licking the mother's vagina. Only with the help of the "midwife" bat was the mother able to finally give birth. Although this is an isolated example of allomaternal care, it may not be unusual in this species. Because Rodriguez flying foxes usually give birth in areas that are difficult to observe, few births in the wild have been documented.

Rodriguez flying foxes are born fully furred. The eyes are wide open and the infant is alert. Because wings are underdeveloped, newborn pups cling to their mothers' bellies and drink from the teats under their mothers' armpits. The pups have sharp milk teeth, which firmly attach to the mother's fur. These milk teeth eventually fall out and are replaced by permanent teeth. The baby stays attached to its mother for about 30 days, until it becomes too heavy to carry, after which it is left at the roost. At about 50 days, the pup starts exploring the roost area and flaps its wings to strengthen them. Interactions with other pups in the roost help to develop social skills.

After 2 to 3 months, pups are flying and are fully weaned, although they still roost with their mothers. Rodriguez fruit bats do not become fully independent until 6 to 12 months after birth. These bats reach maturity at 1 to 2 years of age.

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

Sources have not provided any information on the various forms of parental investment by P. rodricensis . Females provide their young with milk and protection. Also, because pups have a limited ability to regulate their body temperature, the mother's selection and maintenance of a thermal environment are important aspects of parental care. The role of males is not exactly clear. Information on the parental investment of the family Pteropodidae is also limited.

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

Lifespan/Longevity

Information on the lifespan of this species is inadequate, but according to the Lubee Bat Conservancy, Pteropus species can live for approximately 30 years in captivity. The Lubee Foundation has a unique collection of species housed in captivity which includes various species of the genus Pteropus . Observation of other Pteropus species held in captivity indicate that individuals typically live between 9 and 17 years. Pteropus rodricensis is probably similar to other species of the same genus in terms of longevity.

Behavior

Pteropus rodricensis is a very social species. Females roost together in groups, forming a colony, whereas males roost alone. There is a dominance hierarchy among males, and they scent-mark their territory by rubbing the neck, head, and chest on branches. Although most members of the genus Pteropus are active in their roosts during the day, they only leave the roosting area to forage at dusk or in the night. These bats, restricted to a single island valley, are sedentary.

• Key Behaviors
• arboreal arboreal
• flies
• nocturnal nocturnal
• motile motile
• sedentary sedentary
• territorial territorial
• social social
• colonial colonial
• dominance hierarchies dominance hierarchies

Home Range

Rodriguez flying foxes require dense rainforests with large, mature trees. Not only do they roost in these trees, but the trees provide protection from harsh weather. There is no other information available pertaining to the home range of this species.

Communication and Perception

Because Rodriguez fruit bats are frugivores, they do not echolocate. Instead, they have good vision and sense of smell, which allows them to find their food. Since scent marking is used to denote territories, olfactory communication must play some role in this species. No specific information on the communication of P. rodricensis is available; however, other members of the genus Pteropus are known to communicate with vocalizations, which vary depending up on the situation. Also, communication behaviors associated with mating involve vocal, visual, olfactory, and tactile signals. These bats are likely to resemble other members of the genus with respect to communication.

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

• Other Communication Modes
• scent marks scent marks

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

Food Habits

Pteropus rodricensis , a frugivore, uses its sight and smell to find food. Rodriguez fruit bats are nocturnal. At dusk, individuals fly to fruit trees where they feed, rest, digest their food for several hours before returning to the roosting site. Rodriguez flying foxes drink fruit juices by crushing the fruit in the mouth and pressing the tongue against the upper plate. Juice and soft pulp are swallowed, but the bat spits out the skin, hard pulp, and seeds in the form of a pellet. The usual diet consists of bananas ( Musa spp. ), guavas ( Psidium spp. ), mangoes ( Magifera spp. ), papayas ( Carica spp. ), figs ( Ficus spp. ), breadfruit ( Treculia africana ), ripe tamarind pods ( Tamarindus spp. ), flowers, nectar, pollen and sometimes leaves or bark.

• Primary Diet
• herbivore herbivore
  • frugivore frugivore

• Plant Foods
• leaves
• wood, bark, or stems
• fruit
• nectar
• pollen
• flowers

Predation

There is no information available on predators of Rodriguez flying foxes.

Ecosystem Roles

Pteropus rodricensis helps the rainforest to regenerate by dispersing seeds, which are spit out during feeding. This aids recovery of the forest after cyclones and human destruction. This bat also helps to pollinate plants and trees as it feeds off pollen.

• Ecosystem Impact
• disperses seeds
• pollinates
• creates habitat

Economic Importance for Humans: Positive

Rodriguez fruit bats pollinate crops and disperse the seeds of plants and trees. They also eat the fruits that are too ripe to be harvested.

• Positive Impacts
• pollinates crops

Economic Importance for Humans: Negative

Although there are no known adverse effects of P. rodricensis on humans, some farmers mistakenly believe that they damage fruit orchards.

Conservation Status

Pteropus rodricensis is threated with extinction due to habitat loss. In addition to habitat destruction by humans, natural disasters like cyclones have significantly reduced the population. Although cyclones would have had little impact on this species historically, with reductions in rainforest cover, there is currently no buffer provided by additional rainforest when damage occurs because of storms.

Since 1992, Rodriguez flying foxes have been a part of the Species Survival Plan (SSP), and have been successfully breed in captivity. However, it has not yet been reintroduced to its native habitat.

Additional Links

Encyclopedia of Life

Contributors

Valerie Popelka (author), University of Notre Dame, Karen Powers (editor, instructor), Radford University.

Nancy Shefferly (editor), Animal Diversity Web.

References

Altringham, J. 1996. Bats: Biology and Behavior . Oxford: Oxford University Press.

Bat Conservation International, 1995. The Tale of the Flying Fox Midwife. Bats , 13/2: 16-17. Accessed March 30, 2006 at http://www.batcon.org/batsmag/v13n2-7.html .

Braden, M. 2000. "Fact Sheet: Rodrigues Fruit Bat" (On-line). Behavior Matters. Accessed March 31, 2006 at http://www.letus.org/bmatters/animals/bat.html .

Crichton, E., P. Krutzsch. 2000. Reproductive Biology of Bats . London: Academic Press.

Kunz, T., M. Fenton. 2003. Bat Ecology . Chicago: The University of Chicago Press.

SZG Docent, 2006. "Rodrigues Fruit Bat" (On-line). Accessed April 01, 2006 at http://www.szgdocent.org/resource/ff/f-batrod.htm .

Lubee Bat Conservancy. 2004. "Bats at the Center: Pteropus rodricensis " (On-line). Lubee Bat Conservancy. Accessed March 30, 2006 at http://www.lubee.org/center-bats-pteropus_rodricensis.aspx .

Akron Zoo. 2005. "Rodrigues Fruit Bat" (On-line). Akron Zoo. Accessed March 31, 2006 at http://www.akronzoo.com/learn/Rodrigues.asp .

Wildlife Conservation Society. 2006. "Rodrigues Fruit Bat" (On-line). Saving Wildlife. Accessed March 30, 2006 at http://www.wcs.org/5675/aoljump/rodriguesfruitbat .