Megabats, like all bats, are long-lived relative to their size for mammals.
Some captive megabats have had lifespans exceeding thirty years.
Relative to their sizes, megabats have low reproductive outputs and delayed sexual maturity, with females of most species not giving birth until the age of one or two.
Some megabats appear to be able to breed throughout the year, but the majority of species are likely seasonal breeders.
Mating occurs at the roost.
Gestation length is variable, but is four to six months in most species.
Different species of megabats have reproductive adaptations that lengthen the period between copulation and giving birth.
Some species such as the straw-coloured fruit bat have the reproductive adaptation of delayed implantation, meaning that copulation occurs in June or July, but the zygote does not implant into the uterine wall until months later in November.
The Fischer's pygmy fruit bat (Haplonycteris fischeri), with the adaptation of post-implantation delay, has the longest gestation length of any bat species, at up to 11.5 months.
The post-implantation delay means that development of the embryo is suspended for up to eight months after implantation in the uterine wall, which is responsible for its very long pregnancies.
Shorter gestation lengths are found in the greater short-nosed fruit bat (Cynopterus sphinx) with a period of three months.

The litter size of all megabats is usually one.
There are scarce records of twins in the following species: Madagascan flying fox (Pteropus rufus), Dobson's epauletted fruit bat (Epomops dobsoni), the gray-headed flying fox, the black flying fox (Pteropus alecto), the spectacled flying fox (Pteropus conspicillatus), the greater short-nosed fruit bat, Peters's epauletted fruit bat (Epomophorus crypturus), the hammer-headed bat, the straw-colored fruit bat, the little collared fruit bat (Myonycteris torquata), the Egyptian fruit bat, and Leschenault's rousette (Rousettus leschenaultii).
In the cases of twins, it is rare that both offspring survive.
Because megabats, like all bats, have low reproductive rates, their populations are slow to recover from declines.

At birth, megabat offspring are, on average, 17.5% of their mother's post-partum weight.
This is the smallest offspring-to-mother ratio for any bat family; across all bats, newborns are 22.3% of their mother's post-partum weight.
Megabat offspring are not easily categorized into the traditional categories of altricial (helpless at birth) or precocial (capable at birth).
Species such as the greater short-nosed fruit bat are born with their eyes open (a sign of precocial offspring), whereas the Egyptian fruit bat offspring's eyes do not open until nine days after birth (a sign of altricial offspring).

As with nearly all bat species, males do not assist females in parental care.

The young stay with their mothers until they are weaned; how long weaning takes varies throughout the family.
Megabats, like all bats, have relatively long nursing periods: offspring will nurse until they are approximately 71% of adult body mass, compared to 40% of adult body mass in non-bat mammals.
Species in the genus Micropteropus wean their young by seven to eight weeks of age, whereas the Indian flying fox (Pteropus medius) does not wean its young until five months of age.
Very unusually, male individuals of two megabat species, the Bismarck masked flying fox (Pteropus capistratus) and the Dayak fruit bat (Dyacopterus spadiceus), have been observed producing milk, but there has never been an observation of a male nursing young.
It is unclear if the lactation is functional and males actually nurse pups or if it is a result of stress or malnutrition.
Megabats, like all bats, are long-lived relative to their size for mammals. Some captive megabats have had lifespans exceeding thirty years. Relative to their sizes, megabats have low reproductive outputs and delayed sexual maturity, with females of most species not giving birth until the age of one or two. Some megabats appear to be able to breed throughout the year, but the majority of species are likely seasonal breeders. Mating occurs at the roost. Gestation length is variable, but is four to six months in most species. Different species of megabats have reproductive adaptations that lengthen the period between copulation and giving birth. Some species such as the straw-coloured fruit bat have the reproductive adaptation of delayed implantation, meaning that copulation occurs in June or July, but the zygote does not implant into the uterine wall until months later in November. The Fischer's pygmy fruit bat (Haplonycteris fischeri), with the adaptation of post-implantation delay, has the longest gestation length of any bat species, at up to 11.5 months. The post-implantation delay means that development of the embryo is suspended for up to eight months after implantation in the uterine wall, which is responsible for its very long pregnancies. Shorter gestation lengths are found in the greater short-nosed fruit bat (Cynopterus sphinx) with a period of three months.
The litter size of all megabats is usually one. There are scarce records of twins in the following species: Madagascan flying fox (Pteropus rufus), Dobson's epauletted fruit bat (Epomops dobsoni), the gray-headed flying fox, the black flying fox (Pteropus alecto), the spectacled flying fox (Pteropus conspicillatus), the greater short-nosed fruit bat, Peters's epauletted fruit bat (Epomophorus crypturus), the hammer-headed bat, the straw-colored fruit bat, the little collared fruit bat (Myonycteris torquata), the Egyptian fruit bat, and Leschenault's rousette (Rousettus leschenaultii). In the cases of twins, it is rare that both offspring survive. Because megabats, like all bats, have low reproductive rates, their populations are slow to recover from declines.
At birth, megabat offspring are, on average, 17.5% of their mother's post-partum weight. This is the smallest offspring-to-mother ratio for any bat family; across all bats, newborns are 22.3% of their mother's post-partum weight. Megabat offspring are not easily categorized into the traditional categories of altricial (helpless at birth) or precocial (capable at birth). Species such as the greater short-nosed fruit bat are born with their eyes open (a sign of precocial offspring), whereas the Egyptian fruit bat offspring's eyes do not open until nine days after birth (a sign of altricial offspring).
As with nearly all bat species, males do not assist females in parental care.
The young stay with their mothers until they are weaned; how long weaning takes varies throughout the family. Megabats, like all bats, have relatively long nursing periods: offspring will nurse until they are approximately 71% of adult body mass, compared to 40% of adult body mass in non-bat mammals. Species in the genus Micropteropus wean their young by seven to eight weeks of age, whereas the Indian flying fox (Pteropus medius) does not wean its young until five months of age. Very unusually, male individuals of two megabat species, the Bismarck masked flying fox (Pteropus capistratus) and the Dayak fruit bat (Dyacopterus spadiceus), have been observed producing milk, but there has never been an observation of a male nursing young. It is unclear if the lactation is functional and males actually nurse pups or if it is a result of stress or malnutrition.
Megabat