The Grey-headed flying foxes are large bats with dark brown eyes, black wings, dark grey head and body as well as a broad, reddish-brown collar. One of the most conspicuous features of this species is their fur, covering all their body and extending down to their ankles, whereas that of other flying foxes reaches only their knees. This animal is among the largest Australian bats. It has a very long wingspan of more than 1.5 meters.
These bats are found along the east coast of Australia. Their natural range extends from Bundaberg (Queensland) to Melbourne (Victoria). The Grey-headed flying foxes inhabit a wide range of environments such as rainforests, woodlands, mangroves, swamps as well as suburban areas and cultivated lands.
Grey-headed flying foxes exhibit strong social habits. These nocturnal animals form large roosts known as colonies by day, typically in exposed tree branches. They come out of these roosts at dusk to forage, travelling as long as 5 km to their feeding areas. A single colony of these bats may consist of up to tens of thousands of animals. Usually, they don't display territorial behavior, except for the nursing period, when a male will mark the territory of its family (which is simply a space on a tree branch) and the pair will defend its home range against outsiders. Grey-headed flying foxes are known to migrate seasonally, in order to have required amount and type of food. Meanwhile, the abundance of food seems to be the most important factor, since these bats can often be seen in certain camps during the season, when they shouldn't be there. Communication system of this species includes over 20 various vocalizations. Hence, gathering into these large camps, the Grey-headed flying foxes make a very loud noise while communicating with each other.
These animals exhibit a monogamous mating system, where each individual has only one mate during the mating season, which lasts from April to May. Males of this species have scapular glands on their shoulders, which give off characteristic odor, used during the reproductive season. They also emit loud calls to define their territories as well as drive off other breeding males. Gestation period lasts for 6 months, yielding one baby (rarely - twins, although they usually don't survive in the wild), typically in October-November. At 5 - 6 months old, the young bat is weaned. Independence is reached after 6 months of age, while the age of sexual maturity is 30 months old.
Grey-headed flying foxes currently suffer from deforestation, leading to destruction of their natural habitat. Since these animals aren't officially protected from hunting and shooting, they are often killed as pests by farmers. On the other hand, these bats compete for food and habitat with related Black flying-foxes. Moreover, this species is seriously threatened due to mating and hybridizing with Black flying foxes. Additionally, Grey-headed flying foxes are often killed from electrocution as a result of flying into power lines.
According to the Australian Government Department of the Environment, the total population of the Grey-headed flying foxes is around 680,000 (±164,500) individuals. Currently, this species is classified as Vulnerable (VU) on the IUCN Red List and its numbers are decreasing.
Due to their fruit and pollen-based diet, these bats act as key seed dispersers as well as pollinators of the plants they use, thus benefiting the local ecosystem.