Haplonycteris fischeriPhilippine pygmy fruit bat

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Geographic Range

Haplonycteris fischeri, also known as the pygmy fruit bat, or simply the pigmy bat, is found only in some of the Philippine Islands at altitudes ranging from below 100 meters to above 1,500 meters (Nowak, 1999).

Habitat

Haplonycteris fischeri prefers primary forests and is rarely found elsewhere.

  • Range elevation
    0 to 1500 m
    0.00 to 4921.26 ft

Physical Description

The pygmy fruit bat gets its name from its small size when compared to other megachiropterans. The average mass of an individual is between 16 and 20 grams and the average body length is between 68 and 80 millimeters. These bats lack tails, have thumbs measuring up to 25 millimeters in length, and are cinnamon brown with a darker brown head. The number of teeth appears to be reduced in favor of larger individual teeth. The teeth have strongly developed transverse ridges and cusps (Nowak, 1999).

  • Range mass
    16 to 21 g
    0.56 to 0.74 oz
  • Range length
    68 to 80 mm
    2.68 to 3.15 in

Reproduction

Males reach sexual maturity within 11 months, while females reach sexual maturity within 3-5 months. Females usually become pregnant as soon as maturity is reached. Most parous females ovulate between late May and early July, while most young females ovulate between August and September. This means that mating takes place in at least 6 months of the year, and probably more. Upon fertilization, the embryo implants in the mother's uterus, but development then dramatically slows for a period of up to 8 months. After this delay, the rate of development increases and development completes in approximately 3 months, making pregnancy last over 11 months. This makes Haplonycteris fischeri the bat species with the longest known gestation period (Heidemann, 1989). Parturition is followed by 10 weeks of lactation (Nowak, 1999). While many hypotheses have attempted to explain this postimplantation deveolpmental delay, it has been difficult to find concrete answers. In a different species, the hypothesis that the delay coincides with food availability has been tested by providing food in excess and elevating temperatures. Embryonic growth rate was not affected. During this investigation, a temporarily lowered level of plasma thyroxine concentrations was observed in the bats during part of the delay. Further testing using injections of thyroxin daily for up to 40 days also failed to increase the rate of development (Burns & Wallace, 1975). It has also been suggested that environmental cues may trigger the end of the delay, but photoperiod is the most likely candidate, and since the maximum daily change in photoperiod is only 40 seconds in the Philippine Islands, it is unlikely that it is responsible (Heidemann, 1989). (Burns, J. M. & Wallace, W. E., 1975; Heidemann, P. D., 1989; Nowak, R. M., 1999)

  • Breeding season
    May-September
  • Range number of offspring
    1 (high)
  • Average number of offspring
    1
    AnAge
  • Range gestation period
    11 (high) months
  • Average weaning age
    10 weeks
  • Range age at sexual or reproductive maturity (female)
    3 to 11 months
  • Range age at sexual or reproductive maturity (male)
    3 to 11 months

Lifespan/Longevity

Some individuals have been known to live over 10 years (Nowak, 1999).

  • Range lifespan
    Status: wild
    10 (high) years
  • Average lifespan
    Status: captivity
    10 years
    AnAge

Behavior

Communication and Perception

Food Habits

As a frugivore, the pygmy fruit bat eats primarily fruits. It is known to feed on the fruit of Ficus, and most likely of plants of the genus Piper. In addition, it may depend on flowers during certain parts of the year (Heidemann, 1989).

  • Plant Foods
  • fruit
  • flowers

Ecosystem Roles

The pygmy fruit bat, being a frugivore, functions as a seed disperser, and may also be a pollinator while feeding from flowers.

  • Ecosystem Impact
  • disperses seeds
  • pollinates

Economic Importance for Humans: Positive

Since Haplonycteris fischeri lives exclusively in the forest, it has limited interaction with humans, and as it favors forest over agricultural fields, it has little or no negative economic effect on farmers (Nowak, 1999).

Conservation Status

Like many species confined to one type of habitat in islands, the Haplonycteris fischeri population is rapidly thinning. The International Union for Conservation of Nature and Natural Resources (IUCN) states that deforestation is the reason for placing these bats on the vulnerable species (VU A1c) list. The IUCN defines VU A1c as having suffered a reduction of at least 20% over 10 years due to loss of habitat (Hilton-Taylor, 2000).

Contributors

Daniel Huereca (author), University of Michigan-Ann Arbor, Kate Teeter (editor), University of Michigan-Ann Arbor.

Glossary

Pacific Ocean

body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.

World Map

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

frugivore

an animal that mainly eats fruit

herbivore

An animal that eats mainly plants or parts of plants.

island endemic

animals that live only on an island or set of islands.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

year-round breeding

breeding takes place throughout the year

References

Burns, J. M. & Wallace, W. E., 1975. Hormonal control of delayed development in Macrotus waterhousii II. Radioimmunoassay of plamsa estrone and estradiol 17ß during pregnancy. Gen. Comp. Endocr., 25: 529-533.

Heidemann, P. D., 1989. Delayed development in Fischer's pygmy fruit bat, Haplonycteris fischeri, in the Philippines. J. Reprod. Fert, 85: 363-382.

Hilton-Taylor, C, 2000. "Haplonycteris fischeri" (On-line). Accessed October 11, 2001 at http://www.redlist.org/search/details.php?species=9690.

Nowak, R. M., 1999. Walker's Mammals of the World, 6th Ed.. Baltimore: John Hopkins University Press.