Monotremes and Marsupials of Sheoak Ridge

Order Monotremata
Egg laying mammals with mammary glands lacking teats.

A platypus at Sheoak Ridge
A platypus at Sheoak Ridge

Ornithorhynchus anatinus
Recognised today as one of our most iconic Australian species, it was thought that the first platypus specimens sent back to London museums by early scientists were part of an elaborate hoax. How could such a species exist? A furred mammal, with a bill/beak somewhat like a duck, that lays eggs, swims and lives in burrows specially excavated into earthen banks along water ways. This species is truly one of the great wonders of evolution, branching out early only to hit a dead end in terms of speciation.

Feeding behaviour
Platypus feed on small invertebrates living in healthy freshwater creeks and rivers. Aquatic insect nymphs, crustaceans, aquatic worms and other invertebrates make up the majority of their diet. Platypus swim along the bottom of creeks overturning rocks and debri and collecting invertebrates in cheek pouches. Filled cheek pouches are taken to the surface where they quickly masticate their prey with rough plates located along their bill. To find food, they rely on electrical signals picked up by sensitive touch and electro-receptors in their bill.

Platypus typically lay two eggs. The adult male has a bifurcate penis, meaning it has two heads. These are able to fertilise eggs in both of the female ovaries. Laid eggs take 1-2 weeks to hatch, whereupon the young platypus feed on milk secreted from mammary glands on the underside of the female platypus. For protection, male platypus develop two venomous spurs, one of each of their hind legs. The few people who have been poked, have reported very high levels of pain from the venom.

Platypus spotting at Sheoak Ridge

We are lucky enough to have numerous sites along Rifle Creek where platypus are known to breed. We offer our guests guided walks to these sites where we sit in silence and enjoy their often seemingly comical antics. For this activity we recommend long, loose-fitting pants and long sleeved shirts as where there are platypus, there are usually mosquitoes! The odd mozzie bite is worth it, as catching a glimpse of these incredibly unique and secretive Australian animals in the wild is a pretty special experience.

An echidna smelling the breeze
An echidna smelling the breeze

Short-beaked Echidna   Tachyglossus aculeatus

Is there anything cuter than a puggle?
Fossil records indicate larger echidnas were widespread in New Guinea and Australia until around 11,700 years ago (late Pleistocene). However, now there are only four extant species; the short-beaked echidna of Australia and the critically endangered long-beaked echidnas (three recognised living species), found in the highlands of New Guinea. Like the platypus, the male has a spur on its hind leg, but unlike the platypus, no venom gland is functional for this spur.

The primary food for termites is ants, termites, earthworms and other insects. To facilitate this, they have a long, sticky tongue and strong forearms with claws adapted for digging and breaking apart termitaria. Two rough pads (on the back of the tongue and palate) assist them in breaking down the hard exoskeletons of their insect prey. Their range extends all over Australia, with behaviour dependent on local climate.

Here’s where it gets really interesting. Large trains of echidnas can sometimes be spotted during the breeding months of July/August. These trains are led by one receptive female and can have as many as 10 males in attendance. The single egg is laid into the pouch of the adult female 2 weeks after mating.  The egg hatches after around 10 days and the young puggle mops up milk secreted through pores by the mother’s mammary glands. Spines are evident on the young at three months of age.

If threatened, echidnas dig down into dirt with their spines ensuring an effective barrier to potential predators. On hard surfaces, echidnas roll into a ball.

Agile wallaby joey peeking out of Mum's pouch
Agile wallaby joey peeking out of Mum’s pouch

Order Diprodontia
Family Macropodidae

Macropods are marsupials; a group of animals that have evolved a pouch or fold of skin to hold their young. Marsupials give birth to an underdeveloped foetus (unlike placental animals, like humans and dogs that give birth to fully-formed young). The first journey of a joey is from its birthplace of its mother’s cloaca to the awaiting pouch. At around the size of a jelly-bean (dependent on species of course), the joey negotiates the relatively long and entirely independent journey with dogged determination. The physiology of macropods is incredibly interesting and if you are joining us at Sheoak Ridge sometime soon, but sure to ask about the specifics of energetics in locomotion and the intricacies of their reproduction as Claire and Marcus both love to expand people’s minds on these interesting topics.

IMG_1060Red-legged Pademelon
Thylogale stigmatica

These small macropods are found predominantly in rainforest habitat along the east-coast of Australia from mid NSW, stretching up into Papua New Guinea. They can also sometimes be found in wet sclerophyll forests and there are some reports of them occurring in deciduous vine thickets. They eat grasses, rainforest foliage, ferns and fruits. Some of their favourites we have noted while in care with our wildlife rescue program include leaves of the native olive, fig spp. leaves and fruit, Calamus spp., Smilax vines, wombat berry vine foliage and fruit, supplejack vine, fern species (many!) and grasses located on the rainforest edges. In the wild they are usually never far from thick cover, as being a small species, they are predated upon by a wide variety of animals including pythons, birds of prey, wild dogs, dingoes, goannas, quolls and feral cats.
Quiet bushwalkers often hear their ‘alarm thump’ when they disturb them. This sound is made by their hind feet, usually when fleeing from a perceived danger. They will also make this thumping sound when certain smells are evident, like pythons or other potential predators. When interacting with their own species there are several vocalisation sounds they make. Loud raspy hissing sounds are made when males interact or females during breeding to warn males off. Tuk-tuk clucking sounds are made by females to their joeys and by amorous males to females when courting.

Gestation = 28-30 days with the tiny jelly-bean joey crawling from the female’s cloaca after birth, up into the awaiting pouch entirely on their own. The tiny, entirely pink (unfurred) joey will attach to one of the four teats in the mother’s pouch and it’s mouth fuses with this teat until they are 13-18 weeks old. Their eyes open at around this time and it is common to see the small velveting head of a young joey poking curiously from it’s mother’s pouch, munching on whatever it’s mother is eating. This is an important time for gut flora development. At 22-26 weeks, the now fully furred joey begins to leave the pouch for short periods of time, gradually lengthening this until at 26-28 weeks they no longer require the pouch for safety and will follow their mother ‘at foot’. Joeys will still feed from the same, now significantly stretched, teat in their mother’s pouch until they are weaned completely at approximately 10-12 months. Sexual maturity occurs between approximately 12-14months.

These animals are solitary, but large numbers can be sometimes seen together during the evenings when they leave the dense rainforest to feed on more open grassy areas.

Status: Common – despite significant losses to already restricted habitat since European settlement.

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Swamp wallaby at Sheoak Ridge
Swamp wallaby at Sheoak Ridge

Swamp Wallaby
Wallabia bicolor

This species is so unique that it is the only species in this genus (i.e. monotypic). Like the Quokka (a small, yet strangely happy-looking species found in the south western corner of WA and on one small island off the WA coast) the swamp wallaby is another wonder of the natural world, having evolved on a harsh and unforgiving continent. Swampies have 11 chromosomes in males and 10 chromosomes in females, separating them from all other wallabies (they have 16 chromosomes). There are also major differences in skull and teeth, basic behaviour, feeding preferences and reproduction. There are five recognised subspecies of swamp wallaby along the coastline of Australia, with the north Qld subspecies named Wallabia bicolor apicalis (Cape York) and Wallabia bicolor mastersii (Cairns region).

We often tell our guests to really look into the grass as we walk, as we are always being watched by swampies, we just don’t usually see them! They will sit completely still and quiet until danger passes by.

Swampies have a varied diet, eating mainly grasses and shrub/tree foliage. Some of their favourites include Casuarina and Eucalyptus leaves. They love to dig into rotting logs and also eat bark, dirt and roots.

Swamp wallabies are solitary, so the only time you see a few together is a mother with a joey (in pouch or at foot) and males chasing females during breeding. Gestation is 33-38 days. Pouch life is 8-9 months and weaning is complete by about 15 months of age.

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Agile wallabies at Sheoak Ridge
Agile wallabies at Sheoak Ridge

Agile wallaby
Macropus agilis

Agile wallabies are by far the most common macropod brought into care as orphans in FNQ. Individuals and small mobs can be found along roadside edges, particularly during the dry season and often end up as roadkill. Increased traffic, suburban sprawl and more roads through essential habitat mean that the roadkill hits are on the rise. Domestic and wild dogs and cats are also a threat to their existence. While they are currently listed as common and of least concern, their habitat continues to shrink, and increased predators and roadkill undoubtedly threaten their future existence.

Agiles have incredibly big personalities and are a pleasure to rear for release back into safe, wild habitat.

Male agile wallabies are enormous in comparison to the much smaller females. Gestation = 30 days (females exhibit embryonic diapause). The joey begins to leave the pouch for short periods of time from around 5.5 months of age. It will finally leave the pouch at around 10 months of age, but will continue to suckle until around 12 months of age.

Predominantly grass feeders, agiles will also nibble on roots, tubers, selected tree leaves and sedges.

Home range and distribution
Agiles have been tracked traveling up to 13kms in a day, so it is thought they can occupy a large home range (some papers state up to 16ha). They are distributed along the eastern coastline of Australia from around Gladstone (subspecies jardini) up into Papua New Guinea, which is connected to Australia via a land bridge during glacial periods. The species also extends over northern NT (subspecies agilis) and WA (subspecies nigrescens). Agiles are gregarious and can usually be found in small, loose mobs of up to 10 individuals.

An agile wallaby at Sheoak Ridge
An agile wallaby at Sheoak Ridge

Information for these pages came from many sources:

Mammals of Australia 1995 Ed Ronald Strahan Reed New Holland

Australia’s amazing kangaroos: Their conservation, unique biology and coexistence with humans 2012 Ken Richardson CSRIO publishing

Kangaroo: Portrait of an Extraordinary Marsupial 2010 Stephen Jackson and Karl Vernes Griffin Press.

Macropod husbandry, healthcare and medicinals v1&2 2014 Lynda Staker Timeline printing inc.

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A private nature reserve in North Queensland

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