The flying fox (Acerodon jubatus) is a species of megachiropteran bat (giant bat) belonging to the Pteropodidae family. Like all species of this family of chiropterans, flying foxes inhabit the tropical regions of the old world, being A. jubatus endemic to the Philippines. This species is considered one of the largest bats that exist, weighing up to 1.4 kilograms, with a wingspan of up to 1.7 meters.
Acerodon jubatus it was described in 1831 by the German naturalist Johann Friedrich von Eschscholtz. In 1896, Daniel Giraud Elliot described a population of A. jubatus who inhabited the Panay region as Acerodon Lucifer.
However, at the end of the 20th century, this population was designated as a subspecies of the flying fox (A. jubatus lucifer). Later this subspecies was declared extinct.
The flying fox is currently in danger of extinction. The main problem lies in the replacement of plant species that serve as a food resource for this species, by agricultural species or urban areas. Poaching for consumption and sale of their meat also represents a threat to A. jubatus.
Due to this, since 1995, the species was included in appendix I of CITES, being prohibited its hunting and trafficking. However, more effective efforts are needed to protect the Philippine giant flying fox..
These bats are commonly called the flying fox or giant golden-crowned flying fox (in English), due to the resemblance of their face to that of a common fox. They have medium-sized ears that stand upright and a long and moderately robust muzzle..
Acerodon jubatus It is considered one of the largest species of bats. Their body weight ranges from 730 grams to about 1.4 kilograms. In addition, its forearm has a length of 21.5 centimeters, being the longest among the chiropterans..
The wingspan reaches up to 1.7 meters. The skull is elongated and can be approximately 7.2 centimeters long. The male is usually larger than the female.
In the flying fox, the back and rump are dark brown with scattered reddish-brown spots towards the back of the back. This characteristic causes the effect of a dark brown color. In the ventral part the coloration is brown-blackish. Chest, belly and flanks have light hairs.
The neck and its lateral regions are dark and the nape is slightly paler. It has a patch that varies slightly between "chocolate" brown and yellowish and can surround the neck, sometimes reaching the base of the ears..
At the top of the head, above the crown, a golden patch extends that begins between the eyes and can extend to the nape and shoulders. Eyebrows, chin and throat are blackish.
The limbs are brownish black and the wing membranes are brown with pale hues.
The flying fox is dependent on the forests, that is, they are seldom observed outside of them or on their edges, as is the case with other species of flying foxes such as Pteropus vampyrus. This means that A. jubatus it is a species sensitive to disturbances in its habitat.
These animals prefer high-quality secondary forests for foraging activities. They may also frequent streams that contain figs on the banks. It is very rare to observe them in agricultural orchards.
During the day they perch on tall trees and sometimes rest in mangroves located on small islands. Rest places are usually located on steep slopes and cliff edges.
These bats share roosting sites with the giant fruit bats of the Philippines (P. vampyrus) which are much more common and scattered.
This species is endemic to the Philippines. It is scattered throughout much of the country's territory, with the exception of the Batanes and Babuyan island group and the Palawan region. They can be found from sea level to 1100 m.a.s.l. in mountainous forests.
At present, some populations have disappeared in regions where they had been previously registered, such as the Panay region..
Currently there is little information on the reproduction of this species. However, like other megachiroptera species, they have a seasonal and synchronous reproduction. The highest number of births has been registered between the months of April and June.
Flying foxes are polygamous and form reproductive groups, where there is usually a single male with several females (harem).
Females give birth to a single young and carry it by hanging from the fur on the chest and belly until it is fully developed to fly on its own. Females appear to be sexually mature between two and three years of age.
The flying fox feeds on the fruits and leaves of plant species found in lowlands, therefore, these animals are restricted to mature natural forests. The most frequently used plants for food are some hemi-epiphytes and various species of Ficus.
One of the most important species in the diet of A. jubatus it is Ficus subcordata, which in some studies has represented up to 40% of the diet. F. variegata It also represents one of the most common items, providing up to 22% of the total diet of the flying fox..
These plant species are an important source of calcium for these bats. This macronutrient is especially important in bats of the Pteropodidae family..
In the flying fox, the calcium requirements are higher during the lactation period, between the months of May and July. It is at this time that the species of Ficus represent a higher proportion in the diet of these animals.
According to the International Union for Conservation of Nature (IUCN), the species Acerodon jubatus It is in danger of extinction. The population of these bats has decreased by approximately 50% in the last two decades and continues to decrease today.
One of the main causes of this decrease is the loss of their habitat and the intervention in their rest areas..
Illegal hunting is also a strong threat to this species of bats. These animals are hunted for various reasons. Mainly as part of the culture of the Filipinos. They are used as food, considering their meat as a delicacy, and also have several medicinal uses.
On the other hand, they are hunted because they are considered a pest for fruit tree plantations, although they are very rarely seen in these areas. Apparently they are confused with Pteropus vampyrus, that usually perch and feed on these trees.
Currently, flying fox populations in the Philippines are declining. Some estimates of the total population of the flying fox assume that there are currently less than 20,000 individuals of this species.
Historically, mixed bat colonies including several species of the Pteropodidae family have been reported for the country. These colonies are believed to currently only represent 10% of their size 200 years ago.
A recent study has reported that, of 23 groups of perching bats, only in nine groups they found the flying fox. In these mixed colonies, A. jubatus represents a small proportion of total individuals.
In the most protected areas, this species represents up to 20% of the total colony, while in other groups it only represents 5% and in areas with high disturbances, its participation is less than 2%.
Acerodon jubatus It is nocturnal and gregarious. This species is also nomadic and has a high flight capacity, being able to travel between 10 and 87 kilometers per night.
Flying foxes tend to avoid contact with humans. It is for this reason that the foraging localities of these bats are usually isolated areas, in the center of the forests that inhabit.
Some research has shown that these bats show movement patterns during foraging activities night after night. This means that the foraging behavior does not represent a random event in the flying fox..
During the day, the group of bats looks for a resting place. In this place, the flying foxes carry out various activities, among which are mainly sleeping, wing flapping, grooming, spreading wings and resting.
Males are usually more active than females during the day. They carry out courtship activities, defense of territory, fights with other males and spread of scent marks.
Wing flapping is a thermoregulatory behavior, since these animals lack sweat glands. This behavior is correlated with the ambient temperature. So the higher the temperatures (around noon and in the morning) the higher the frequency of flapping..
Grooming plays an important role in regulating ectoparasites that invade flying foxes, such as bat flies (Cyclopodia horsfieldi).
Although in general, the courtship system of flying foxes has been little studied, various behaviors related to reproduction have been recorded. Males usually establish mating territories, marking tree branches with scent, by rubbing the head and neck with these surfaces..
This behavior occurs more frequently during the late afternoon hours, just before embarking on the flight to search for food..
On the other hand, the courtship behavior of the male towards the female, shows a higher frequency from dawn to mid-morning, and decreases from noon to night. During courtship, the male approaches a female and begins to smell or lick her genital area.
Females often reject the male by displaying aggressive behaviors, such as screaming and jerky flapping, and then move away from the male. However, the male continues with the courtship, insisting on this behavior approximately every 5 minutes, until the female accesses copulation..