Gray-headed flying fox
| Gray-headed flying fox | ||||||||||||
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Gray-headed flying fox with outstretched wings |
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| Pteropus poliocephalus | ||||||||||||
| Temminck , 1825 |
The gray-headed fruit bat ( Pteropus poliocephalus ) is a species from the group of actual fruit bats (Pteropodini) living in eastern Australia within the fruit bats (Pteropodidae).
features
The gray-headed flying fox is one of the largest species of bat found in Australia. Its wingspan is often one meter, in some cases up to 1.5 meters. Its body is dark gray, the head is light gray. Its red-brown shoulder area is striking. The membranes are black. Like all fruit bats, it has no tail. Claws sit on the first and second fingers. The species is the only one among the fruit bats in which the fur reaches to the ankles, in other species it only reaches to the knees.
The body length is between 23 and 29 centimeters, on average these fruit bats are 25 centimeters long. Their weight is 600 to 1000 grams, some specimens can reach more than 1 kilogram. Your forearm is 13.8 to 18 centimeters long.
The head of this subgroup of bats is similar in shape to that of a fox or dog, which has led to the common English name Flying Fox and the German name flying fox . They do not orient themselves by echolocation using ultrasound , but rely on their large eyes when flying. Therefore, the hearing organs characteristic of other bat groups are also missing.
distribution
Gray-headed fruit bats are distributed along the east coast of Australia between Bundaberg in Queensland via New South Wales to Melbourne in the state of Victoria . They inhabit a relatively narrow coastal strip that extends in the north of New South Wales to the western slopes of the Australian Cordillera , in the south it is somewhat narrower and includes only the zone east of the mountains.
The distribution area has recently decreased, especially in the north, earlier it reached to Rockhampton in central Queensland. The cause is the climate change and the associated advance of the black flying fox into the range of the gray-headed flying fox. The habitat of the gray-headed fruit bat is believed to have increased in the south, but accurate data is lacking. In any case, the populations of the flying fox comprised several million individuals in the 1930s, today there are only a maximum of 400,000. Between 1989 and 2001 alone, the population decreased by 30 percent.
Way of life
At dusk they leave their resting places - called camps - and go in search of food. They can cover up to 50 kilometers in one night in order to reach seasonal feed sources or feed sources that only occur in certain areas. Their diet consists of nectar, pollen and fruits of various plants such as eucalyptus , banksias and myrtle heather . They follow people into the suburbs, where they also feed on plantation fruits such as mangoes , figs and grapes . They are therefore persecuted as pests in these areas. They are also unpopular near the settlements because of the strong smell near the camps , which the males in particular give off. Their ecological importance lies in the distribution of the pollen and seeds of the plants they visit.
The females only give birth to one cub per year, which is born in October or November after a six-month gestation period. In the first three weeks, the young animal is carried on the evening flights. In the following two months, the young remain on the sleeping trees, as they are not yet able to fly, and are suckled by their mothers. They do not leave the camps until they are around three months old , but they are not weaned until they are six months old and then feed on their own.
Danger
The decline in the population is mainly due to the clearing of coastal forests in favor of settlements and agricultural areas. Many forage plants of the gray-headed fruit bat are also affected by deforestation. This leads to a lack of food, especially in winter, especially among the offspring. Disruption of sleeping places by humans and the pursuit of fruit bats in the vicinity of the settlements also occur. There is also danger from power lines and fences, which can injure the animals. Between 1994 and 2002, around 24,500 gray-headed fruit bats died of overheating ( hyperthermia ) on 19 days when the daily temperature rose to over 42 ° C. On January 12, 2002, in the Australian summer, there were 1361 animals alone. 92 orphaned and dehydrated young animals could be collected and cared for. The number of days of extreme heat in southern Australia has increased over the past decade. On one weekend in mid-February 2017 alone, thousands of gray-headed fruit bats died in the Richmond Valley Council from air temperatures of up to 46 ° C. Due to extreme dehydration , media reports said they "just fell dead out of the trees".
The spread of the black fruit bat, which has penetrated 500 kilometers into the habitat of the gray-headed fruit bat since 1990, is related to the higher average temperatures. The area of the black flying fox in the north of Australia is limited by the frost that prevails on some winter days in the south and is poorly endured by this species. However, the milder winters caused by global warming have shifted this frost line. As resources become scarcer, this creates further food competition for the gray-headed fruit bat.
The species was therefore upgraded in 2008 on the IUCN Red List from "least concern" to "vulnerable".
The only EAZA holders are in Israel, former holders are Antwerp and London.
literature
- NB Simmons: Order Chiroptera. In: DE Wilson, DM Reeder: Mammal species of the world: a taxonomic and geographic reference. 3rd edition, Johns Hopkins University Press, 2005, ISBN 0-8018-8221-4 , pp. 312-529.
- P. Menkhorst, F. Knight: A field guide to the mammals of Australia. Oxford University Press, 2001, ISBN 0-19-550870-X .
Individual evidence
- ↑ Gray-headed flying fox (Pteropus poliocephalus) ( Memento of the original from June 25, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. at Arkive
- ↑ Information at Animal Diversity Web
- ^ A b Greg Richards (Ed.): Proceedings of a workshop to assess the status of the Gray-headed Flying-fox. University of Sydney, April 29, 2000 full text ( April 10, 2011 memento in the Internet Archive )
- ^ F. Ratcliffe: The flying fox (Pteropus) in Australia. Bulletin of the Council for Scientific and Industrial Research (Australia), 53, Melbourne 1931
- ^ P. Eby and D. Lunney: Managing the gray-headed flying fox, Pteropus poliocephalus as a threatened species: a context for the debate. In: P. Eby and D. Lunney: Managing the gray-headed flying fox Pteropus poliocephalus as a threatened species in NSW. Royal Zoological Society of New South Wales, pp. 1-15, 2002
- ↑ JA Welbergen, SM Klose, N. Markus and P. Eby: Climate change and the effects of temperature extremes on Australian flying-foxes. Proceedings of the Royal Society Series B, 275, pp. 419-425, 2008
- ^ Thousands of bats drop dead from trees in Australia heatwave. Retrieved February 18, 2017 .
- ^ D. Lunney, G. Richards & C. Dickman: Pteropus poliocephalus. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4. Online , accessed November 15, 2010
- ↑ [1] ZTL 16.6
Web links
- Information at Animal Diversity Web
- Information and photos at arkive.org
- Pteropus poliocephalus onthe IUCN Red List of Threatened Species . Retrieved November 14, 2010.