Pteropus bats live over 20 years in captivity. Most adult females conceive each year and give birth to one young; there are no records of twin births, though superfetation (two fetuses of different ages from separate conceptions) has been documented. Pregnancy lasts six months and lactation for 5-6 months. Mating, parturition and rearing of young occur in large camps (Martin et al., 1987), often composed of several species (Nelson, 1965a).
Tan et al. (1997) report that C. brachyotis formed harem groups, with one to four females and their young associated with one mature male. The male usually roosts separately from the females, who remain in physical contact with one another. They could not distinguish whether the harems were based on female-defense or resource-defense polygyny. Males are territorial, especially as mate selection takes place. Males mark territories by rubbing their scapular glands along branches; ritualized fighting between males is most intense during this period. Harem fidelity varies greatly among pteropid species. Male P. poliocephalus may be polygamous or monogamous. Homosexual behavior is common, especially among males (Nelson, 1965a).
The breeding season appears regulated by male fertility, which is tightly linked to photoperiod (Martin et al., 1987), though Nelson (1965a) reports that male P. poliocephalus will try to initiate copulation throughout the year. During breeding periods, pairs may copulate several times a day. Precopulatory behavior includes mutual grooming and extensive licking by the male, of the female’s vagina. Juvenile males also display this behavior, and males frequently attempt to lick females’ genitalia outside the mating season (Nelson, 1965a).
Most births occur in a short period for each species, but there is significant spread in “late” births (Martin et al., 1987). Parturition takes from 10 min to over 7 h; as soon as the infant’s head appears, the mother licks vigorously and the infant soon starts licking its lips and nose. Mothers usually eat the placenta, but other members of some P. poliocephalus colonies have been observed joining in (Martin et al., 1987). Nelson (1965a) writes that following parturition, “no traces of [the placenta] were found on the floors of the cages, or on the ground under the camps, and… puerperal females shot at this time had blood in the lumen of the undamaged gut.”
Author: S. Cobey.