Flying Mammals Bats

The vegetarians

Australia has some of the world's largest fruit bats. Many of these can be seen throughout the Wet Tropics, particularly at dusk when they leave their camps in the trees to forage for food during the night. Their main diet is nectar and fruits and they play a vital role in the dispersal of rainforest seeds. They will also take pollen and help to cross-pollinate flowers as they lap nectar. These bats are common in backyard gardens, too - especially when the pawpaws (papaya) have ripened!

The most common is the Spectacled Flying-fox (Pteropus conspiculatus) which boasts a wingspan of roughly one metre (3 feet). A good place to see these impressive bats rise up from the canopy and depart for their daily feed is from a boat on the Daintree River. There are many areas though, even in the inner suburbs of Cairns, where flying foxes can be seen hanging from tree branches during the day. A single young is produced in late spring and females are capable of reproduction at two years of age. These bats have excellent vision and sense of smell and can travel up to 20km in one night in search of food.

Not all the fruit bats are so large. They range in size down to the tiniest Queensland species, the Blossom Bat (Syconmycteris australis), with a body only 5cm (2 inches) long and weighing in at a meagre 15 grams (half an ounce). It shelters under leaves during the day but at night, its pointed snout and brush tongue (similar to the lorikeets) allow it to feast on the nectar hidden deep in flowers, making it an important specialist pollinator of the rainforest.

Some other flying-foxes to look for in this area are the Black (Pteropus alecto), the Little Red (Pteropus scapulatus) and the striking Tube-nosed (Nyctimene robinsoni), easily identified by the yellow spots on its wings.

The insect terminators

The Blossom Bat described above might be a heavyweight compared to some of the insect eating bats! These are the sonar-equipped bats whose calls sound like high pitched shrieks and clicks. Another name for them is microbats (as opposed to the fruit bats which are also called megabats).

There are many species of microbats and identification often requires trapping and detailed examination by an expert. Sophisticated technology is also being used to identify bats by electronic signature analysis of their calls. The majority of microbats roost in caves but several species use tree hollows, tunnels, roofs and under loose tree bark. Most of these bats are very small, having bodies as light as 4 grams (.15 of an ounce) although many of the Wet Tropics species are about 20 grams (.7 of an ounce) and are 4 to 6 cm (1 ½ to 2 ½ inches) long.

Insectivorous bats are usually seen around streetlights at dusk and appear like large, fast flying insects themselves, whirling and turning as they use their sonar to catch insects in mid-flight. When spotlighting in the forest, flashlight beams can attract moths, which in turn, attract microbats. Flashes of their wings can be seen as the bats pursue their prey through the beam of light.

We hear so many reports of wildlife facing extinction, that the story of the Tube-nosed Insectivorous Bat is welcome news. Once credited with being Australia’s rarest mammal, this tiny microbat (it weighs 8 grams) has made a dramatic reappearance thanks to new research techniques. Until 1994 only six of these bats had ever been caught, all of them in the Wet Tropics. But with new trapping techniques - in particular a harp trap of superfine fishing line which fools their sonar, and recent major advances in bat call detection, sensitivity and analysis - many more of these bats have been found in various locations around the World Heritage Area. Tiny transmitters also have been used to track animals to communal nesting sites and learn more about their behaviour. While the bat is still classified as rare, scientific research has been able to shed new light on how we can protect its habitat to help ensure its continuing survival.

The Tree Kangaroos

Lucky you are if you come across a tree-kangaroo in the forest and actually get to see it! Often, the only evidence of a tree-kangaroo's presence is the sudden crash of leaves and branches followed by a thud as the very shy tree-kangaroo jumps from its lofty hiding spot and flees into the bush. Some tree-kangaroo sightings are simply that of a long, brown furry tail disappearing into the undergrowth.

The Wet Tropics is home to Lumholtz's and Bennett's Tree-kangaroos. Both stand no more than 60cm (2 feet) tall but their tails are almost a metre (3 feet) long. They spend most of their time in the tree canopy feeding on leaves and fruits.

The Lumholtz's Tree-kangaroo

Lumholtz's Tree-kangaroo (Dendrolagus lumholtzi) occurs mostly at high altitudes between Kirrama (in the southern Wet Tropics area) to Mt Spurgeon (in the northern Wet Tropics but south of the Daintree River). A generally solitary animal, small groups of up to four can sometimes be seen. A single young is produced and there appears to be no specific breeding season. It is nocturnal and spends the day crouched on a branch sleeping.

The Bennett's Tree-kangaroo

Bennett's Tree-kangaroo - Photo by Michael ProcivA little larger than Lumholtz's Tree-kangaroo is the Bennett's Tree-kangaroo (Dendrolagus bennettianus). It resides at high and low altitudes north of the Daintree River in an area of only about 70km by 50km (44 miles by 31 miles).

Possums and Gliders

The Wet Tropics region supports the highest possum diversity in Australia. This exceptional diversity is even more extraordinary in that there are five possums which are endemic (found nowhere else). All of them except one - the Mahogany Glider - are rainforest specialists. They are the Herbert River Ringtail (Pseudocheirus herbertensis), the Lemuroid Ringtail (Hemibelideus lemuroides) brown and rare white colour morph, the Green Ringtail (Pseudochirops archeri) and the Daintree Ringtail (Pseudocheirus cinereus).

The rainforest species are restricted to the uplands and, as a consequence, they occur as a number of isolated populations. One example is the Lemuroid Possum which occurs only above 550 metres on the Atherton Tablelands but which has a smaller population on the Carbine Tablelands. The Carbine population of the Lemuroid occurs only above 1,000 metres and is characterised by many more "white" furred individuals.

Other possums and gliders can also be found in the Wet Tropics:

* the black and white Striped Possum;
* the tiny Long-tailed Pygmy Possum also found in New Guinea;
* the Squirrel, Greater, Feathertail and Sugar Gliders;
* the Yellow-bellied Glider, also sometimes called the Fluffy Glider;
* the Coppery Brushtail (a colour form of the very common Brushtail Possum which ranges down the east coast of Australia);and
* the Common Ringtail.

Mahogany GliderThe critically endangered Mahogany Glider (Petaurus gracilis) was thought to have been extinct since the 1800's but a living specimen was found in 1989. This glider is not rainforest dependent and prefers low woodland on swampy coastal plains, beach ridges and Melaleuca swamps. It eats nectar, tree sap, tree gum, lichens and invertebrates. This glider has been the subject of a government program to buy back critical habitat for the species as land clearing is the greatest threat to the glider's survival and most of its range falls outside the protective status of World Heritage.

Green Ringtail - Photo by Mike TrenerryThe Green Ringtail is so named for the strange illusion of colour provided by the black, yellow and white banding on each hair of its thick fur. It is easy to recognize during spotlighting as it has white patches below its ears and eyes. This possum's diet consists almost entirely of low protein, high fibre leaves, especially those of fig trees, and will also take ripe figs. The Green is the most solitary of the possums and does not have a den. It sleeps on branches by curling itself forward so that it resembles a large furry ball. This lack of a den may also explain why its single young clings to its mother's back longer than any other possum. Predators of this quiet and sedate possum include the Rufous Owl, the Spotted-tailed Quoll and the Amethystine Python.

The emblem of the Queensland Parks and Wildlife Service is an attractive black and white ringtail possum from upland and highland altitudes. The Herbert River Ringtail is also known affectionately as 'Herbie'. This ringtail likes leaves with a very high protein content, unlike the Green Ringtail. Their den is usually in a tree hollow or in large epiphytic ferns. Two young are produced and after nearly four months, they are ready to leave the pouch. The brown juveniles only require another two weeks being carried on their mother's back before they are ready to strike out on their own.

The White-tailed Rat

While most rodents will make a hasty retreat from human visitors, one not so easily intimidated is the White-tailed Rat (Uromys caudimaculatus). This large rat has a body length of 30cm (1 foot) and the end half of its 33cm (13 inch) tail is white and without fur (which is the easiest way to identify them). The White-tailed Rat can be seen on the forest floor at night but it is just as likely to be seen climbing around tree branches. Although most rodents are known for their powerful teeth, this one can eat through the hardest of seed coats. The next time you find a coconut on the ground with a perfectly round hole about 2 cm (3/4 inch) in diameter drilled through it, you will know that a White-tailed Rat found it first!

Another ground-dweller is quite the predator. An attractive but elusive night-time hunter of both the forest floor and the canopy is the Spotted-tailed Quoll, also known as the Tiger Quoll. There are two species of quoll in the Wet Tropics: the northern subspecies of the Spotted-tailed Quoll (Dasyurus maculatus gracilis) and the smaller Northern Quoll (D. hallucatus). They are well known for their aggressive dispositions, described in books as "pugnacious", "ferocious" and "savage". The Quoll is a carnivore, preferring rodents, small macropods, birds and reptiles, although large insects, some fruit and even carrion is included in their diet. The Quolls are not quite standard marsupials in that they don't have a real pouch. During breeding season, the skin around the female's nipple area extends into a flap which partially covers the young. Females have 6 teats but the number of young born can range from one to eight. Young remain in the pseudo-pouch for several weeks before being left in a nest hollow or cave and attended to by the female. Independence is usually reached by 18 weeks and sexual maturity is at one year.

There are many other mammals to look for in the Wet Tropics such as Melomys (native rats), Hydromys (the water rat whose fine swimming abilities evoke images of the river otter), Northern Brown Bandicoots (often seen darting across roads at night), their paler rainforest cousins the Long-nosed Bandicoot, Agile Wallabies (look for them hanging around the golf courses of the Northern Beaches area of Cairns), and the adorable Red-legged Pademelon.

The Tropical Bettong

Another interesting but very rare ground-dwelling mammal is the Tropical Bettong (Bettongia tropica). This strictly nocturnal animal has been found at only a few places in the Wet Tropics but not normally in rainforest, preferring the more open forest types on the drier western side of the Great Dividing Range. Looking a bit like a small kangaroo bent forward but having a pointed face shape, it feeds mostly on fungi and seems to have a special digestive system to obtain nutrients from this unusual diet.

The Musky Rat-kangaroo

In the morning look for the Musky Rat-kangaroo (Hypsiprymnodon moschatus), a very dark brown marsupial macropod (kangaroo family) whose body is only about 23cm (9 inches) long foraging for fruits on the rainforest floor. This animal is regularly seen around the volcanic lakes Eacham and Barrine and around the bases of the famous Curtain Fig and Cathredral Fig trees on the Atherton Tablelands. The Musky Rat-kangaroo prefers the wetter parts of the forest and feeds on fallen fruits found in the leaf litter as well as small invertebrates such as earthworms and grasshoppers. They give birth to two or three babies which stay in their mother's pouch for about 21 weeks before emerging to spend most of their time in their forest floor nest. When they are a little older, they will accompany the female on her feeding rounds.

Mammals - General Information

The Wet Tropics region is home to about a third of Australia's 315 mammal species - including unique green possums, fierce marsupial cats, kangaroos which climb trees and rare bats. As well as relatively common mammals like the platypus and wallaby which are widespread over the continent, the Wet Tropics is home to 13 mammal species which are found nowhere else in the world. All except two of them - the endangered Tropical Bettong and Mahogany Glider - are rainforest dwellers. They include two tree-kangaroos, a rat-kangaroo, four ringtail possums, a melomys and an antechinus.

Other Wet Tropics mammals are found in rainforest to the north in Cape York - the striped possum, prehensile-tailed rat, and the white-tailed Rat. Others also occur in to the south - the yellow-footed antechinus, spotted-tailed quoll and the white-footed dunnart (found 4000km south in Victoria and Tasmania).

Some of the Wet Tropics rainforest species have close relatives in New Guinea and Southeast Asia. When Australia became isolated after the break-up of the supercontinent of Gondwana, it drifted northward. About 15 million years ago it bumped into the Asian continental place. This collision allowed an exchange to take place between two sets of animals and plants which had evolved in isolation. Asian flora and fauna, including many placental rats, moved into Australia. At the same time Australian species moved north. Many of them colonised New Guinea, a new high altitude land mass created by the 'bow wave' of Australia's northerly drift. As a result, some of the unusual mammals of the Wet Tropics also live with our northern neighbours - the Long-tailed Pygmy Possum in Papua New Guinea and the Tube-nosed Insectivorous Bat in Southeast Asia.