The common name for this bat is Marianna flying foxes (Pteryopus mariannus Desmarest, 1822). Synonyms are Pteropus keraudren, Quoy and Gaimard, 1824, Pteropus paganesis, Yamashima, 1932, and Pteropus ulthiensis, Yamashima, 1932.
Chemical scent marking plays a role in establishing territories and grooming plays a role in establishing and maintaining social bonds. Other species of flying foxes take part in aerial displays, vocalization that varies with the situation, and scent marking. Pteropus species do not echolocate, instead they use their excellent vision in low light and their sense of smell to find food and navigate.
Communication Channels: tactile ; chemical
Perception Channels: visual ; tactile ; acoustic ; chemical
Marianna flying foxes are currently listed as threatened by the U.S. Fish and Wildlife Service and endangered by the IUCN. They are also on CITES Appendix I. The cause of their decline is habitat loss by timber removal, natural disasters, and through the destructive habits of non-native, invasive ungulates. Populations are also in decline as a result of hunting for food and killing as a crop pest.
US Federal List: threatened
CITES: appendix i
State of Michigan List: no special status
IUCN Red List of Threatened Species: endangered
Marianna flying foxes often eat the fruits of cycads, which makes their meat toxic and can lead to a neuropathological disease called amyotrophic lateral sclerosis-Parinsonism dementia complex, eventually leading to death. These bats also bioaccumulate DDT and other toxins.
These bats are an important cultural food for the native people of the Marianna Islands, and they will often risk fine and imprisonment to have Marianna flying foxes. Their role as pollinators and seed dispersers is also a positive impact on the native ecosystems of the southwestern Pacific islands.
Positive Impacts: food
Flying foxes in general are keystone pollinators and seed dispersers in the southwestern Pacific. They are the only native frugivorous mammals in that region and are very important in forest regeneration through seed dispersal.
Ecosystem Impact: disperses seeds; pollinates; keystone species
Marianas flying foxes are frugivorous, but also eat flowers and leaves on occasion. They forage in agroforest, pandanus savanna, swamp forests, and sometimes visit coconut groves. Their favorite fruits are breadfruit (Artocarpus mariannensis, A. altilis), papaya (Carica papaya), Cycas circinalis, figs (Ficus spp.), Pandanus tectorius, Terminalia cattappa, flowers from Ceiba pentandra, and coconut (Cocos nucifera). These bats have been observed traveling 10 to 12 km to reach feeding grounds.
Plant Foods: leaves; fruit; nectar; flowers
Primary Diet: herbivore (Frugivore )
Marianas flying foxes, Pteropus mariannus, are found on Pacific islands ranging from the Japanese Ryukyo Islands in the north, south to Guam. They are found on Guam, the Marianna Islands, Micronesian islands, Okinawa, and the Ryukyo Islands.
Biogeographic Regions: oriental (Native )
Other Geographic Terms: island endemic
Most of the islands on which Marianas flying foxes are found are tropical or subtropical. Large colonies can be found roosting in stands of native forest, smaller groups are found in isolated patches of native forest or in coconut tree groves (Cocos nucifera) groves. Forests these bats are found in usually have sparse undergrowth, a canopy that reaches 8 to 15 meters and scattered with taller trees that tower above the dominant canopy. Preferred roosting trees are C. nucifera, Ficus prolixa, Ficus species, Hibiscus tiliaceus, and Pandanus tectorius.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: forest ; rainforest
Other Habitat Features: riparian
Nothing could be found on the lifespan of this species. In captivity, Pteropus species have been know to live about 30 years.
Marianas flying foxes are medium-sized bats, weighing 330 to 577 grams. Their forearms measure 34 to 54mm. Wingspans range from 860 to 1065 mm. Overall length, from snout to rump, is 195 to 240mm. Males are usually a little larger than females. Mariana flying foxes are handsome bats, with black to brown fur over most of their body, flecked with silver hairs. The shoulders (mantle) and the sides of the neck are bright yellow to golden-brown. Their distinctly fox-like head, which gives these bats their name, is brown to dark brown. They have well-formed, rounded ears and large eyes.
Range mass: 330 to 577 g.
Range length: 195 to 240 mm.
Range wingspan: 860 to 1065 mm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes alike; male larger
Marianas flying foxes have few natural predators. There are only two that are known, brown tree snakes (Boiga irregularis) and humans. Humans will use these bats for their meat or kill them for consuming fruit crops. It's also possible that large owls will take these flying foxes while they are foraging at night.
Known Predators:
Marianas flying foxes are polygynous. Males form harem groups within breeding colonies. Non-breeding males will form bachelor groups or live on their own. (Wiles, 2004). In harems, males are usually accompanied by 2 to 15 females. In Guam, the average sex ratio was observed to be 38 to 72 males per 100 females. Mating mostly occurs during the day in the harems but will occasionally occur at night.
Mating System: polygynous
Reproduction occurs year-round. In Guam, mating and nursing have been observed throughout the year, indicating no apparent peak in births. Females give birth to one offspring per year. Gestation length is 4.5 and 6 months. Age at weaning and first flight is unknown. Sexual maturity occurs between 6 and 18 months of age. Other Pteropus species become sexually mature at 18 months.
Breeding interval: Females give birth to one offspring each year.
Breeding season: Breeding occurs throughout the year.
Range number of offspring: 1 to 1.
Range gestation period: 4.5 to 6 months.
Range age at sexual or reproductive maturity (female): 6 to 18 months.
Range age at sexual or reproductive maturity (male): 6 to 18 months.
Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
Young bats are carried by their mothers until they are too large to carry any longer. They are then left at the roost while the mother forages. While roosting, females fold their pup into their wings, and the large lump that creates in the mother's silhouette can be seen from a distance.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female)
The Mariana fruit bat (Pteropus mariannus), also known as the Mariana flying fox, and the fanihi in Chamorro, is a megabat found only in the Mariana Islands and Ulithi (an atoll in the Caroline Islands).[3] Habitat loss has driven it to endangered status, and it is listed as threatened by the US Fish and Wildlife Service. Poachers and food hunters, other animals, and natural causes have led to the decline.
The Mariana fruit bat is a mid-sized bat which weighs 0.6 to 1.1 lb (270 to 500 g), and has a forearm length of 5.3 to 6.1 in (13.4 to 15.6 cm). Males of the species are slightly larger in size than the females. Their abdomens are colored from black to brown, while also having gray hairs. The mantle and the neck are a brighter brown to golden brown color and the head varies from brown to black. Their ears are rounded and their eyes large, giving them the features of a canid, so many megabats are called flying foxes.[4]
The bat is considered a culinary delicacy by Chamorros. Eating fruit bats is linked to a neurological disease called lytico-bodig disease. Paul Alan Cox from the Hawaiian National Tropical Botanical Garden in Kalaheo, and Oliver Sacks from Albert Einstein College in New York, found the bats consumed large quantities of cycad seeds, and - like some eagles, which were shown to build up levels of the pesticide DDT in fat tissue - probably accumulate the toxins to dangerous levels.[5]
In 2001, the population was estimated to number between 300 and 400 bats on Sarigan.[6] The current population numbers are unknown, but one known concentration is on Ritidian Point in Guam.[7] In 2013, Bat Conservation International listed this species as one of the 35 species of its worldwide priority list of conservation.[8]
Johnson and Wiles described roosting behavior: "Sarigan's population differs from those of larger islands in the archipelago by usually having smaller roost sizes, typically 3–75 bats, and large numbers of solitary bats that at times comprise up to half of the population. Colonies and smaller aggregations were composed primarily of harems with multiple females, whereas a nearly equal sex ratio occurred among solitary animals."[6]
Pteropus mariannus has three subspecies:[3]
{{cite journal}}: Cite journal requires |journal= (help) The Mariana fruit bat (Pteropus mariannus), also known as the Mariana flying fox, and the fanihi in Chamorro, is a megabat found only in the Mariana Islands and Ulithi (an atoll in the Caroline Islands). Habitat loss has driven it to endangered status, and it is listed as threatened by the US Fish and Wildlife Service. Poachers and food hunters, other animals, and natural causes have led to the decline.
