Feature, News from the Field

Discovering Australia’s remarkable rodents

23 Oct. 2023
Brad Leue/AWC

Australia is home to more than 60 species of native rodents found nowhere else in the world. They are a range of shapes and sizes, and each have evolutionary adaptations designed to help them populate every bioregion of the continent.

From the Rakali, an otter-like rodent with webbed feet, to tiny desert-dwelling hopping mice that weigh no more than a golf ball and move like miniature kangaroos, Australian native rodents are diverse. They are also in danger of disappearing.

Since 1788, mainland Australia has lost 11 native rodent species to extinction. They are particularly susceptible to predation by feral cats and foxes, land clearing, competition with pest rodents, and introduced diseases. These ongoing threats place surviving species at serious risk of extinction.

Rodents are an important part of Australia’s biodiversity, making up a quarter of our mammal species. They play many roles in Australian ecosystems, from seed predators to seed dispersers, and are a major prey item for birds, reptiles and other mammals.

At AWC, we are providing hope to Australia’s native rodents through our extensive land management practices – creating feral predator-free safe havens, implementing appropriate fire regimes, and undertaking intensive weed removal. We are also focusing on feral predator control, for both cats and foxes as well as the removal of feral herbivores from areas in which they pose a threat to native rodent habitats.

Meet some of the remarkable rodent species found on AWC sanctuaries and partnership areas and learn what we’re doing to protect them.

Greater Stick-nest Rat
Leporillus conditor

A Greater Stick-nest Rat at the entrance of a nest at Mt Gibson Wildlife Sanctuary. Brad Leue/AWC
A Greater Stick-nest Rat at the entrance of a nest at Mt Gibson Wildlife Sanctuary.

Sometimes called ‘Stickies” the Greater Stick-nest Rat is one of the larger native rodents, growing between 17-26 centimetres in body length and weighing up to 450 grams. They have fluffy yellow-brown to grey fur on their back and cream fur below, with a blunt snout, large, dark eyes and large, rounded ears.

The mainly nocturnal species builds large communal nests using sticks, dry grass, and stones. These nests can be up to one metre high and 1.5 metres wide, with tunnels leading from the outside to the centre of the structure where the animals place grass and other soft green vegetation.

The nests can be incredibly intricate, with multiple chambers and levels, and so strong they are almost impossible to pull apart. This sturdy construction is partially due to the Greater Stick-nest Rat’s sticky urine, known as amberat, which acts as an adhesive to glue the sticks together.

Nests can reach such grand proportions because they are built upon over several generations, occasionally even acquiring additional structures nearby. Up to 20 Greater Stick-nest Rats may occupy a nest at a time to shelter from predators and temperature extremes.

What is AWC doing?
Once ranging across semi-arid regions of southern Australia, including parts of Western Australia, South Australia and western New South Wales, the species declined rapidly after European settlement, disappearing entirely from the mainland by the 1930s.

A captive breeding program was established in 1985, and the species was subsequently released on several offshore islands in South and Western Australia. As numbers built up, Greater Stick-nest Rats have been reintroduced to several mainland predator-free fenced areas.

The Greater Stick-nest Rat is not the easiest species to manage: several attempts have been made to reintroduce ‘stickies’ to properties managed by AWC, including Yookamurra, Scotia and Faure Island. None of these reintroductions persisted. In 2011, AWC conducted our first successful  translocation of the species to one of our predator-free safe havens, establishing a population at Mt Gibson Wildlife Sanctuary. This population was supplemented with four other translocations from 2015 to 2019.

Additionally, in September 2020, AWC returned 40 Greater Stick-nest Rats to mainland Australia’s largest (9,570 hectares) feral predator-free area at Mallee Cliffs National Park, in partnership with the NSW National Park and Wildlife Service.

Spinifex Hopping Mouse
Notomys alexis

A juvenile Spinifex Hopping Mouse. Andrew Morton/AWC
A juvenile Spinifex Hopping Mouse.

The Spinifex Hopping Mouse, also known by one of its traditional names Tarkawara, thrives in the arid zone of Australia and can be found throughout Central and Western Australia, occupying both spinifex-covered sand flats and stabilised sand dunes.

Slightly larger than a common mouse, the nocturnal species grows up to 13 cm long and weighs just 35 grams, with light-brown fur with a white belly. Named for its hopping gait, somewhat similar to that of a kangaroo, its long hind legs and tail allow the mice to move quickly to escape prey.

Like many desert-dwelling mammals, hopping mice are highly adapted to living in harsh desert climates and can go without drinking – sourcing all their water from the food they eat. However, their most unique feature is the way in which they have evolved over time to conserve water.

This species of hopping mouse is said to have the most efficient kidneys, however small, allowing them to produce the most concentrated urine of any mammal recorded. The kidneys extract every drop from their waste, so the urine is so concentrated it is pretty much solid and consists of only the waste material that they want to get rid of from the body.

What is AWC doing?
Continued feral predator management programs are providing a safe environment in which the Spinifex Mouse can thrive. The ongoing establishment of appropriate fire regimes in desert environments is also providing habitats with the reduced threat of wildlife and habitat destruction.

Central Rock-rat
Zyzomys pedenculatus

A Central Rock-rat translocated into the 9,450 hectare feral predator free safe haven at Newhaven Wildlife Sanctuary in the Northern Territory. Brad Leue/AWC
A Central Rock-rat translocated into the 9,450 hectare feral predator free safe haven at Newhaven Wildlife Sanctuary in the Northern Territory.

The Central Rock-rat is one of five native Australian rock-rat species. This nocturnal, medium-sized (70-150 g) rodent survives on just a few high mountain ridges in Central Australia in tussock and hummock grasslands, low shrublands and low open woodlands. These habitats occur on ridge tops, cliffs, scree slopes, hills and valley floors. The species once occurred over a much larger area of central and western Australia.

Considered one of Australia’s most endangered mammals, this stout, fluffy desert rat, has thick yellowish-brown coloured fur on the upper body with a lighter fur on the lower body and grows to a head and body length of up to 15 cm.

The species has a thickened tail at the base, presumably a fat store during good conditions like a number of other desert mammals. The tail is slightly longer than its body and is densely furred, with tufts of hair at the tip.

The species are known to lose their tails when captured, and can also shed fur and skin very easily, helping them to scurry away from predators.

What is AWC doing?
Once found across a broad swathe of central and western Australia, the Central Rock-rat has disappeared from over 95% of its pre-European distribution. After a sighting in 1960, the species seemed to have disappeared and was considered likely extinct for nearly 30 years. It ‘reappeared’ in the early 2000s.

In July 2022, a joint team of ecologists from AWC and the Northern Territory Government’s Flora and Fauna Division, working in collaboration with Traditional Owners, trapped rock-rats from sites across Tjoritja/West MacDonnell National Park and airlifted them by helicopter to the safety of a large, feral-free, fenced area at AWC’s Newhaven Wildlife Sanctuary.

In addition to the Central Rock-rats released at Newhaven, 16 individuals were taken to Alice Springs Desert Park, where they became founders of a new captive breeding program that aims to boost numbers for subsequent releases. The program has been successful with a number of these offspring having been released at Newhaven.

A huge part of AWC’s work moving forward will be to continually monitor and study the translocated Central Rock-rat population, making sure that they thrive, breed, and establish a self-sustaining population.

Bush Rat
Rattus fuscipes

An adult Bush Rat photographed at Curramore Wildlife Sanctuary, Queensland. Wayne Lawler/AWC
An adult Bush Rat photographed at Curramore Wildlife Sanctuary, Queensland.

Measuring about 16 cm in length, Bush Rats have soft grey-brown fur and pink-grey feet. Their tails are brown to black, almost free of hair, the same length or slightly shorter than their bodies. Unlike black rats, which they are sometimes mistaken for, the Bush Rat has more of a rounded head and a blunt shaped nose, with chisel-shaped front teeth. Bush Rats may weigh between 65 g to 225 g, with males being slightly larger than females.

They are nocturnal, and shelter during the day in short burrows or grass-lined nests under logs or rocks. The species is very territorial, but during spring and summer time travel great distances to forage and mate, with males covering distances of up to a kilometre each night.

While widespread across forested parts of Australia, after disturbance they can be pushed out of their territories by the invasive black rat, which it competes with for food and habitat.

What is AWC doing?
In 2011, AWC worked with researchers from Sydney University to conduct a trial reintroduction of 50 Bush Rats to North Head, Sydney. Subsequently, between 2014 and 2016, AWC successfully reintroduced 170 Bush Rats to the sanctuary, with the goal of establishing a self-sustaining population.

The reintroduction program was part of a unique initiative to use native wildlife to outcompete a foreign species (invasive black rats) and act as a biological control. The reestablishment of the locally-extinct Bush Rat (and their ecological processes) has been very successful and is helping to restore Sydney’s lost biodiversity.

Surveys indicate that the population of black rats at North Head has decreased from an estimated 112 in 2019 to 29 in 2020. The decline continued in May 2021, when only nine black rats were captured during a survey of 250 hectares at the sanctuary.

AWC also conserves Bush Rats at a number of our Wildlife Sanctuaries in eastern Australia, including Brooklyn, Mount Zero-Taravale and Curramore.

Embracing the diversity of native rodents

Around one quarter of Australia’s mammals are rodents. They are integral to ecosystem functionality; not only are they a vital part of the food chain for other native predators, but they also contribute to other ecological processes including seed dispersal and predation.

Continued research, monitoring, and intervention are needed if we are to protect and conserve these and other species of native rodents for the future.

Here are some of the other native rodent species found on AWC sanctuaries and partnership areas:

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