Native mammal behaviour

The range of behavioural characteristics of Australian mammals is so vast it would be impossible to outline each one specifically. We will cover the most common species within the different groups. Australian mammals are classified as:

• Monotremes: These are animals that have fur, lay eggs and suckle their young. Examples are:

- platypus

- echidnas.

• Diprotodontia: These are marsupial mammals––a majority are herbivorous. Examples are:

- kangaroo

- wallaby

- possum

- koala

- wombat.

Monotreme: Short beaked echidna The short beaked echidna (Tachyglossus Aculeatus) is a solitary animal and not aggressive toward other echidnas. They have a home range rather than a territory and the area of this home range has been found to average 50 hectares. The home range of one echidna will overlap with that of others.

Echidnas have no fixed nest or shelter sites, except for burrows dug by females for use as incubation and nursery chambers. They simply take refuge wherever appropriate during periods of inactivity. This usually takes place at night, as echidnas are diurnal animals, foraging for their diet of termites and ants. This activity pattern can be shifted in response to environmental conditions, especially heat.

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This is a photo showing an echidna busy foraging! Other characteristics of echidnas are:

• Echidnas have no sweat glands and do not pant. Although they show remarkable tolerance for low body temperatures, they are highly vulnerable to heat stress. To avoid these high temperatures, the echidna may shift its activity to the cooler morning and afternoon (crepuscular), or even become completely nocturnal.

• Echidnas are defensive animals. Their response to the approach of danger is avoidance. They will disappear inside a log or wombat or rabbit burrow, or they will remain motionless in a clump of vegetation. However, if it is caught in an exposed position, the echidna will dig straight down rapidly, leaving only a patch of spines visible. Look at the photo below and see if you can spot any echidnas!

• In the colder habitats of the echidna’s distribution, this monotreme can become dormant. This is achieved by lowering their body temperature and metabolic rate to preserve energy and is a means of surviving during bad weather––eg snow.

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Monotreme: Platypus The platypus (Ornithorhynchus anatinus) is a solitary animal and yet you can find large numbers using a small area of water. We do not know how territorial platypuses are and yet, there is evidence of the platypus defending specific areas of its range. Other important points are:

• Foraging for food takes place mainly around dawn and dusk. Factors such as locality, human activity, day length, air and water temperatures and the abundance of food may override this activity pattern. In certain places and at certain times of the year, the platypus may actually become strictly diurnal or nocturnal. It is possible that the platypus is capable of becoming torpid (dormant).

• When not in the water, a platypus spends most of its time in a short, simple burrow just above the water level, with the entrance usually under a tangle of tree roots. The nesting burrow, constructed by the female prior to laying eggs, is a far more elaborate structure. It may be up to 20 metres long, plugged with clumps of earth at intervals, ending in a chamber containing a nest of damp vegetation.

• Vigorous grooming of the fur is most important. This sometimes occurs in the water but is more usually carried out on a particular log or rock.

• The platypus has a range of vocalisations. A low growling sound is made by an individual when disturbed.

Platypuses are shy animals and photographing them in the wild requires endless patience. So far, this is the best that this writer has achieved despite many hours of quiet waiting!

Diprotodontia: Koalas Koalas (Phascolarctos cinereus) are aggressive, solitary animals. They are arboreal and largely nocturnal marsupials. They spend most of the day

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asleep in a tree fork. Unlike most other marsupials, koalas do not actively seek shelter. The koala is the only arboreal marsupial that lacks a tail.

Here is a photo of a koala sitting in a gum tree!

Other important points about koalas are:

• Koalas become extremely active just after sunset, eating, grooming and changing branches. They may descend to the ground, adopting an awkward high-stepping gait. Koalas can move quite quickly on the ground and are also capable of swimming if necessary. The koala feeds predominantly on the foliage of eucalypts. As eucalypt leaves have a high water content, koalas don’t need to drink water often but they do drink on occasions.

• Older males will attempt to monopolise a number of females by marking out their territory with the secretion from glands on the chest and by bellowing. Their bellows, which warn off other suitors, can be heard several kilometres away.

• When stressed or alarmed, koalas will adopt a typical alarm posture, sitting bolt upright with ears erect and eyes wide open.

• They urinate and defecate frequently and vocalise, making hiccup-like noises and low whining sounds.

• Aggressive behaviour is characterised by head shaking and ear flicking. The koala will often attempt to bite and may raise either one or both arms before swiping with its claws.

• When extremely ill the koala may become lethargic and adopt a ball-like posture, lowering its head and drooping the ears.

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Diprotodontia: Wombat (Wombatus ursinus) Wombats are generally nocturnal, although in cooler climates it may become diurnal (alternate between day and night). They are solitary animals graze on pasture, herbs and eat shallow roots. Although they are solitary, their home ranges overlap and other wombats are tolerated. Meetings are uncommon.

As well as the common wombat, there are two species of wombat, both with hairy noses: the northern and southern hairy nosed wombats.

Other important points are:

• The teeth of the wombat are like those of the rodent and continually grow throughout their life. The wombat has a reputation for being slow and clumsy, yet can actually reach speeds of 40km/h and cover an area of 20 hectares.

• The wombat has the most developed brain of all the marsupials.

• The wombat is an excellent digger and life revolves around the burrow, where it shelters from the heat. Interconnected burrows are made in a common area and may be up to 30 metres long to avoid confrontations. Adult females and their young, as well as juveniles, generally inhabit the outer burrows of the warren, while mature males shelter in central burrows.

This photo shows a wombat enclosure with the rock and logs.

• Signs of stress in the wombat are shown by teeth gnashing and loud

screams. Aggression is demonstrated by charging with simultaneous scratching and biting. Although attacks may occur without warning, the wombat will often utter low growls. Occasionally, it will flee rather than attack.

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This is a photo taken of an exhibit showing a replica of two wombats—one with the common shiny nose and another with a hairy nose.

Diprotodontia: Possums and gliders Possums and gliders are nocturnal marsupials––they are extremely diverse. We will focus on the brush-tail possums, pygmy possums, feather tail gliders. In general, possums and gliders will:

• vocalise when threatened

• defend themselves by scratching and biting and may urinate as a defence.

Brush-tail possums

Brush-tail possums (Trichosurus vulpecula)—as can be see in the photo below—are active climbers and most nest in tree hollows. Some that survive in suburbia may choose to nest in the roof of homes, or in possum nesting boxes in trees that have been built and supplied for them.

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Other important points are:

• The brush-tail possum is a solitary animal with a well-defined territory, which the male will defend aggressively, especially during the breeding season. The territory is marked out using secretions from the scent glands, which stain the possums’ fur red.

• It is a competent climber, readily leaping from tree to tree. Some time is also spent on the ground searching for food, including eucalypt leaves, fruits, buds, bark and occasionally clover and other pasture plants. Meat may be eaten, if offered, as well as many human foods—as can be seen in the photo below of a possum helping itself to some cake!

• When threatened, the common brush-tail possum will hiss and bark, often prior to biting and scratching.

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Pygmy-possums

These are small nocturnal possums. The smallest is the little pygmy-possum (Cercartetus lepidus), weighing in at just seven grams as an adult. Most pygmy-possums eat insects and some will feed on pollen and nectar. The mountain pygmy-possum (Burramys parvus) may even store seeds as a food reserve for the alpine winter. Other important points are:

• Pygmy-possums have strong prehensile tails. With the exception of the mountain pygmy-possum, all species are arboreal.

• They seek shelter in nests constructed from leaves and shredded bark that are often made in tree hollows.

• Torpidity is a feature of these possums and generally lasts for several days. It is a protective mechanism that occurs when food is scarce or temperatures are low. Given their size, pygmy-possums find it difficult to maintain body temperature under adverse conditions, so they may enter a state of torpor to conserve energy.

Feathertail glider (Acrobates pygmaeus)

This glider uses its feather-like tail to break and steer the animal as it glides. The feather-tail glider is a nocturnal, arboreal marsupial. Its gliding membrane is the shortest and thickest amongst all the gliders. With a weight of only 15 grams, it can glide for over 20 metres. Other important points are:

• Its footpads have fine grooves, allowing the glider to suspend itself upside down.

• The feather-tail glider is a social animal, sheltering in groups in leaf-lined nests.

• It feeds on small insects, nectar, blossoms, foliage and plant exudate (sap).

• During the cold months, this glider may become torpid, especially when food is scarce.

Ringtail possums

This group of possums are nocturnal, capable climbers, with strong prehensile tails. The ringtail possum is largely arboreal, with the exception of the rock ringtail possum (Pseudocheirus dahli), which spends most of the time on the ground. Other important points are:

• All feed on the foliage of trees supplemented by fruits and blossoms. Given their adaptation to suburbia, some, such as the common ringtail possum (Pseudocheirus peregrinus) have become accustomed to feeding on the fruit and vegetable scraps of humans.

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• The common ringtail possum is a solitary possum. It is slightly more sociable and less aggressive than the common brush-tail possum. This allows the territories of neighbouring common ringtail possums to often overlap with one another.

• Nests are built of twigs, lined with dense vegetation.

The larger gliders

This group is most active during the first half of the night, when they feed on insects, nectar and plant exudates. The greater glider (Petauroides volans) feeds almost exclusively on young eucalypt leaves. These larger gliders take shelter in leaf-lined tree hollows during the day. Other important points are:

• Most of the larger gliders are sociable and most nest in small colonies with home ranges of neighbouring colonies overlapping. They tend to be aggressive towards members of other colonies.

• Male sugar gliders (Petaurus breviceps), for example, will scent mark all members of their colony and attack unscented gliders without hesitation.

• The gliders in this group are vocal animals and some species, such as the yellow-bellied glider (Petaurus australis), will call loudly before gliding, to maintain contact with the group.

The photo belows shows a greater glider photographed in Ben Halls Gap Forest.

Diprotodontia: Macropods Macropods are generally nocturnal animals, grazing and foraging from dusk to early morning (nocturnal). The western brush wallaby (Macropus irma) is one of the exceptions, being crepuscular, sleeping during the day and night

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and grazing early morning and late afternoon. Some species may become diurnal during the cool or wet weather. Other important points include:

• Most macropods seek shelter during the day. Many of the smaller species build and shelter in nests, while other species shelter in dense undergrowth, under trees or in rock crevices.

• Other species, such as the red kangaroo (Macropus rufus), do not actively seek shelter and often spend the day basking in the sun.

• Amazingly, macropods inhabit almost all of Australia’s environments but do not occur above the snowline.

As can be seen in this photo—a very distinct white albino kangaroo.

• Macropods may be either solitary or social animals. In some species,

males live in a mixed group and will establish a hierarchy through wrestling and sparring with other males. The dominant male is likely to mate with the females.

• Signs of stress in macropods include licking of forearms, body flinching, trembling, head and ear shaking and teeth-grinding.

This is a photo of a rock wallaby hiding amongst the rocks.

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Diprotodontia: Dugong behaviour The dugong is a large, herbivorous aquatic mammal. It is found in shallow, warm coastal waters where it grazes on seagrass. Its powerful tail can propel it at speeds of up to 22 km/h. It uses its paddle like forelimbs to steer and can push itself along the seabed with them. Dugongs may live for 55 or more years.

Diprotodontia: Flying fox behaviour Flying foxes are nocturnal and forage almost exclusively at night. The time that they set out from camp depends on food availability. If food is scarce or a long way away then the flying foxes tend to set out before sundown.

When food is plentiful, they wait until after dark before setting out. Usually, the flying foxes leave the camp in a stream, which sometimes circles the camp before setting out in the direction of the food source. The peak return to the camp usually occurs just before dawn, but again is affected by distance and food availability. The following are other important points:

This is a photo of a flying fox with its wings spread—these animals are very vocal.

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• Flying foxes usually establish their camps in tall and reasonably

dense vegetation. Large numbers, and continual usage, can lead to severe damage to trees, sometimes even killing them. Black and grey headed flying foxes often camp alongside creeks or rivers.

• There are a number of different types of camps used by flying foxes—some are more or less permanent, although the number of flying foxes using it may vary from time to time, while others are seasonal, used only for a limited time.

• During the summer months, the young are born and raised and mating occurs. During this time, the camps are very noisy and there is activity throughout the day. At other times of the year, the camps are quieter and generally smaller. Major population shifts usually occur between April and September and often, small transitory camps occur where there is an abundance of food.

• Flying foxes hang upside down in the trees in their campsite. Normally they hang by both hind feet but can hang from one, with the other folded down. The wings are used for thermoregulation—in cold or wet weather, they are wrapped around the body for protection. In hot weather, a wing can be used like a fan.

• Flying foxes can ‘walk’ along a branch by moving their feet. To move more rapidly, they also use their forelimbs, with the wing membranes folded and using the thumb.

• To defecate and urinate, they invert themselves and hang by their thumbs. They then shake their pelvis and then resume the hanging position.

• To take off, a flying fox flaps its wings until the body becomes almost horizontal, which unlocks the tendons that hold their toes at right angles while roosting.

• Flying foxes spend a lot of time grooming themselves. This probably helps maintain the waterproof covering on the wings.

• Flying foxes are very vocal animals and this is important in their social behaviour. Over 30 different types of calls have been recorded in the grey headed flying fox, including mother-young, male-male, male-female, female-female. Their hearing ability is similar to humans.

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Diprotodontia: Microbat behaviour Microbats are nocturnal and all are insectivorous except the ghost bat, which eats small mammals. They have small eyes and hunt by echolocation. This means that they send out high-pitched ultrasound, produced by the larynx. This is reflected back by objects, received by their large external ears and used to navigate.

Microbats have a large body surface over which to lose heat and also use large amounts of energy in flight. In cold weather, they may become torpid or hibernate. When hibernating, their body temperature is only a few degrees above that of the environment. When awakening, they need to use muscles to bring their body temperature up before they can fly.

During the day, microbats may roost in caves, tree hollows or rock crevices. Some roost inside curled leaves or under tree bark and some enter buildings.

The freetail bats tend to use hollows, whereas the bent wing bats tend to use caves, bridges and culverts.

Dasyurid The dasyurids groups of animals include quolls, dunnarts, antechinuses, Tasmanian devil, thylacine, numbat. Dasyurids are carnivorous marsupials. They are vocal marsupials equipped with an acute sense of smell and sharp teeth. The termite-eating numbat (Myrmecobius fasciatus) is specialised for this exclusive diet, where its teeth are only used by juveniles—the adults do not chew their food!

• Dasyurids are nocturnal and either arboreal or terrestrial. Moving about rapidly at night, their diet ranges from insects and other invertebrates to small mammals and birds.

• The Tasmanian devil (Sarcophilus harrisii) is less of a predator and more of a scavenger, largely feeding on carcasses from road kills.

• During the day, most dasyurids will seek shelter in burrows, rock crevices or leaf-lined tree hollows.

• In general, the territory of the dasyurid is well defined with urine and faeces. Some species, such as quolls and the antechinuses, are solitary and extremely aggressive animals. Although mainly insectivorous, the antechinus may kill mammals its own size, such as mice.

This photo is of ‘Molly’ a Dasyurid chewing on a finger.

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• Death of the male soon after mating is a natural phenomenon seen

in antechinuses and some of the phascogales. This may be related to increased levels of activity adversely affecting the immune system, thereby making the animal more susceptible to infections.

• Torpor is seen in several of the dasyurids, including the common dunnart (Sminthopsis murina), the western quoll (Dasyurus geoffroii) and the kowari (Dasyuroides byrnei).

• Dasyurids will either attack or retreat if threatened. Most will initially display open mouth type behaviour, baring their teeth. The Tasmanian devil may become aggressive, huffing, growling or even screaming while baring its teeth and snapping its jaws.

Bandicoot and bilby (Macrotis lagotis) Bandicoots and bilbies become active at night. Insects and other arthropods make up the greater part of food for typical bandicoots but the diet may be supplemented as opportunities arise, by small rodents, fruit and soft tubers. Other important points are:

• Bilbies are reported to be the most carnivorous, hunting on small mammals and lizards but their diet primarily consists of insects and their larvae, seeds, bulbs, fruit and fungi.

• During the day, bandicoots rest in a shallow scrape in the ground that is lined with vegetation. The bilby will seek shelter in a burrow, which like the wombat’s burrow, may be complex and extensive. The bilby and the wombat are the only burrowing marsupials.

• Male and female bandicoots are aggressive, territorial and solitary. The bilby however, may live singly or in small family groups, although males are often very aggressive towards one another.

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• When threatened, these marsupials generally become immobile, freezing in position, although some will attempt to escape. The bilby is more vocal than the other bandicoots and may hiss and growl at the threat.

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