Grey-headed flying foxes (Pteropus poliocephalus) 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 reaching up to 1 m (3 ft 3 in).
The overall color of the pelage is a dark-grey body with a light-grey head, separated by a reddish-brown collar. The fur on the body is long and streaked with grey, the broad and well-defined collar completely encircles the neck with hair that is golden orange in tone. A unique characteristic among bats of the genus Pteropus is fur on the legs that extends all the way to the ankle. Like many megachiropterans, the species lacks a tail. All of these bats possess claws on their first and second digits. The head is simple in form, with the characteristic 'dog-like' appearance of the genus. Since it does not echolocate, it lacks the tragus or leaf ornamentation found in many species of Microchiroptera. It relies on smell and, predominately, sight to locate its food (nectar, pollen and native fruits) and thus has relatively large eyes for a bat.
These bats are found along the east coast of Australia. Their natural range extends from Bundaberg (Queensland) to Melbourne (Victoria). Grey-headed flying foxes inhabit a wide range of environments such as rainforests, woodlands, mangroves, and 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, traveling as long as 5 km (3 miles) 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 the 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. The communication system of this species includes over 20 various vocalizations. Hence, gathering in these large camps, Grey-headed flying foxes make a very loud noise while communicating with each other.
Grey-headed flying foxes are herbivores (frugivores, nectarivores). They particularly favor eucalyptus blossom, although they are also known to consume fruits, pollen, nectar, and bark.
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 a characteristic odor, used during the reproductive season. They also emit loud calls to define their territories as well as drive off other breeding males. The 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 the 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 by 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 fox 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.