Medium flying squirrel bag
| Medium flying squirrel bag | ||||||||||||
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Medium flying squirrel bag |
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| Petaurus norfolcensis | ||||||||||||
| Kerr , 1792 |
The Middle Gleithörnchenbeutler ( Petaurus norfolcensis ) is a kind of the nocturnal glider (Petauridae) and belongs to the genus of the Glleithörnchenbeutler ( Petaurus ). It is far less known than its smaller relative, the short-headed gliding pouch ( Petaurus breviceps ) and is therefore often confused with it.
features
As its name suggests, the Middle Gleithörnchenbeutler is a medium-sized representative of its genus. With a head-trunk length of around 18-25 cm, it is roughly twice as large as the short-headed glide bag. Its weight is 190–330 g. Its fur is greyish on the upper side, with a black to brown stripe on the back from the head over the trunk to the tail, where it then ends or widens and turns the whole tip of the tail black. The bushy tail is about the same length as the rest of the body and the hairs get shorter from the base to the tip. On the belly side, the fur of the Middle Gleithörnchenbeutler is white and in female animals the pouch is located here.
The flight membrane typical of the Petaurus genus stretches on the sides of the body between the wrists and the ankles of the hind legs during gliding, creating a square flight pattern (unlike the giant gliding bag, in which the opening of the sliding membrane in the elbow area creates a triangular flight pattern). The thin membrane is normally hairy on the top and slightly less on the underside. When climbing and running around, it is hidden in the flank fur, which makes the animals look quite plump.
Differences to the short head gliding bag
Apart from the difference in size, the medium-sized flying squirrel bucket looks very similar to its smaller relative. However, it has a clearer facial drawing than the Kurzkopfgleitbeutler. His head is also longer and more pointed, and his ears are longer and narrower. Its tail is bushier than that of its smaller relative, especially at the base. The white tip of the tail, as it occurs in the Kurzkopfgleitbeutler, does not exist in the Middle Gleithörnchenbeutler. He has only gray and black tail tips.
Way of life
Medium-sized flying squirrel bucks are nocturnal tree dwellers with an average life expectancy of around three to five, sometimes six years in the wild. In captivity, they grow significantly older, up to eleven years.
They live in groups of one male, one or two females and their offspring each year. One group lives in several tree hollows within their three to five hectare area . Due to the great affinity to their territory, the animals usually do not move, even if large parts of them are destroyed. The males mark their territory with the help of a well-developed scent gland on their foreheads.
Medium-sized flying squirrel buccaneers spend the night in tree hollows lined with leaves. These are preferably spacious inside, but the entrance is as narrow as possible and thus inaccessible to potential enemies. The Middle Gleithörnchenbeutler collect leaves for the nest lining. Here they hang upside down on a branch with their hind legs and break off the leaves with their front legs. Then they take hold of the bundle of leaves with their tails and carry it to the cave, where they moisten the leaves with urine and use it to line the cave. This gradually creates a spherical nest in the tree.
Life in the trees is made possible for the Middle Gleithörnchenbeutler not only by their climbing skills, but also by the characteristic of gliding, which is typical of the Petaurus genus . When jumping from a high tree, the gliding squirrel baggers stretch their front and rear legs, thereby tightening the gliding membrane. According to Ludwig Heck , they offer “a very peculiar sight: as if the animal suddenly lost all physical thickness and became a towel, so to speak”. In this way, they can slide up to 50 meters to the next tree, although this naturally depends on the height of their jump. With their long, bushy tail, they control their trajectory in the air and can thus also deviate from their original target to another. At the next tree, the animal lands upside down, wraps its tail around the trunk and spirals up around the trunk, where it then jumps off again. Young medium-sized gliding squirrel pouches often sit on their mother's back when gliding, who is sometimes carrying the next offspring in the pouch.
Reproduction
The mating season of the Middle Gleithörnchenbeutler ranges from June to January. During this time the females will have a well-developed pouch that contains four teats. After a gestation period of around three weeks, they give birth to one to three, but mostly two, young, which immediately crawl into the mother's pouch and stay there for at least ten more weeks. The young middle glide pouches spend the next six weeks in the nest, there their fur develops completely and their eyes open around the 85th day of their life. At the age of 110 to 120 days, the offspring slowly go foraging with their mother. When they reach sexual maturity, they leave the group at 12 to 18 months.
food
The mean squirrel bucket is omnivorous . Its diet is seasonal, but typically consists mainly of nectar and pollen from eucalyptus flowers and invertebrates such as insects and spiders . Compared to the other species of flying squirrel, the medium sized flying squirrel bucket eats significantly more insects.
In order to get to plant secretions (for example the juice of certain eucalyptus species or acacia resin ), he scratches trees with his sharp teeth and licks up the secretions. Another source of nutrients is the honeydew . Occasionally it can also happen that a common flying squirrel hunted small vertebrates .
distribution and habitat
The distribution area of the Middle Gleithörnchenbeutler stretches in a wide band from northeast Queensland over the east of New South Wales to southeast Victoria . However, it has also been reported that representatives of this species have been sighted on the border between Victoria and South Australia .
Open eucalyptus forests and eucalyptus woodlands from sea level up to 1200 m above sea level, but also coastal forests in Queensland are preferred to be inhabited . Usually these are rather dry forests, but in some cases the Middle Gleithörnchenbeutler also inhabit more humid forest areas that border the rainforests in southeastern Queensland. It is important that the trees provide enough caves and that the shrub layers of banksia or acacia ensure a nectar supply over the winter.
In urban areas too, for example in the parks and gardens of Brisbane , there are medium-sized flying squirrel hives, but they are rarely seen due to their nocturnal lifestyle.
Their range is generally very patchy, as the fragmentation of their habitat means that they can often only inhabit small strips of forest.
Danger
Natural enemies of the mean flying squirrel buccaneer are mainly monitor lizards , bag martens , pythons and owls . But wild animals such as dogs and cats are also a threat to him.
The main threat, however, comes from humans: due to the deforestation for firewood and special purpose wood, mass clearing for agriculture and also due to urbanization, the quality and size of the remains of the Middle Gleithörnchenbeutler's habitat decrease. There are also too few matching tree hollows in many of its habitat fragments, and the regeneration of trees and bushes is often made more difficult by grazing animals (e.g. rabbits and kangaroos).
In the IUCN redlist, the species is listed as not endangered (least concern), on the grounds that the species is widespread and has what is believed to be a large population. In addition, it occurs in some protected areas and it is unlikely that their number will decrease to such an extent that they can be listed as endangered (“Listed as Least Concern in view of its wide distribution, presumed large population, occurrence in a number of protected areas , and because it is unlikely to be declining at nearly the rate required to qualify for listing in a threatened category. "(2008)).
Since the population of the Middle Gleithörnchenbeutler is still shrinking, it is recommended to install nest boxes to reduce damage, to research the ecological needs of the animals and the influence of habitat changes and, furthermore, to expand habitat protection in state forests and in parks. The population should also be closely monitored, especially in peripheral and isolated areas.
literature
- Lexicon of Biology . 6th volume. Spectrum Akademischer Verlag, Heidelberg 2001, ISBN 3-8274-0331-6
- Bernhard Grzimek: Brockhaus - The Library (= Grzimeks Encyclopedia Mammals. Volume 1). Brockhaus, Leipzig 1997, ISBN 3-7653-6110-0
- Walter Fiedler (Ed.) Mammals 1 (= Grzimeks Tierleben. Volume 10). Kindler, Zurich 1967
- Michael Schröpel, Norbert Neuschütz Zoo animals lexicon. Deutsch Harri, Thun 1989, ISBN 3-8171-1106-1
- Dietrich Starck (Ed.) Part 5, Mammals 1 (= textbook of special zoology. Volume 2, vertebrates) SAV, 1995, ISBN 3-334-60453-5
Web links
- Petaurus norfolcensis . IUCN; accessed January 23, 2013
- Petaurus norfolcensis . Wildlife Queensland; accessed January 23, 2013
- B. Lundrigan, M. Girvin: Petaurus norfolcensis . Animal Diversity Web, 2000; accessed January 23, 2013
- Petaurus norfolcensis, Review of Current Information in NSW . (PDF; 503 kB) NSW Scientific Committee; accessed January 23, 2013
- Coral Rowston: The Squirrelglider: an Auteological Study in Fragmented Landscape (PDF; 1.0 MB) January 1998; accessed January 23, 2013
Individual evidence
- ↑ Textbook of special zoology . Volume 2: Vertebrates (Part 5: Mammals 1). P. 360
- ↑ Petaurus norfolcensis . Animal Diversity Web
- ↑ Grzimek's animal life . Volume 10, Mammals 1 , p. 116
- ↑ environment.nsw.gov.au (PDF) NSW
- ↑ Squirrel glider . ( Memento of the original from January 2, 2013 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. Wildlife Queensland:
- ^ IUCN redlist
- ↑ Petaurus norfolcensis in the IUCN Red List of Threatened Species .
