Rats and mice can get a pretty bad rap. They’re generally considered to be pests, carriers of disease, and unwelcome visitors. But while many people think of marsupials as Australia’s iconic animal emblems, Australia is also home to around 60 species of native rats and mice.
Our native rodents have a fascinating evolutionary history, arriving on the continent in two waves – the “Old World” rodents dispersed from Asia over 4 million years ago while sea levels were low, and the “new endemics” followed a few million years later. Since that time, our native rodents have become established in just about every habitat across the country, from the arid deserts to the rainforests to the coasts.
The key to their success is rodents’ ability to diversify and adapt. Recent research has shown that, despite the large number of rodent species in Australia, their skull shapes are relatively similar, which may explain why they are able to hop from one niche to the next with relative ease.
An excellent example of this flexibility is the rakali, a semi-aquatic rat that grows up to weigh over a kilogram, making it one of the largest rodents in Australia. Not only is the rakali equipped with webbed feet and water-resistant fur that allow it to thrive in waterways, it has even been observed to consume the toxic and invasive cane toad. With surgical precision, the rakali flip the toads to remove and eat the heart and liver, avoiding the poisonous glands.
Another large rodent, the black-footed tree-rat, prefers a drier habitat – it has evolved to live in forested areas, nesting in tree hollows during the day and foraging at night. Its sharp claws allow it to climb trees with ease.
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At the other end of the size spectrum, the tiny pookila, or New Holland mouse, is about the same size as an invasive house mouse but much less stinky. You won’t find it under your roof, though – the pookila prefers open heathland and coastal areas, where it plays a vital role in seed dispersal.
To help them survive and thrive in this variety of habitats, Australia’s native rodents have also developed some pretty neat social strategies. The greater stick-nest rat might not be able to burrow or climb trees particularly well, but they do know how to build a very fine castle. They construct huge nests out of sticks and dried grass that they share with their families. When the male offspring reach maturity, they head off into the world to look for mates, while the females stay in or near the nest they were born in.
The greater stick-nest rats aren’t the only builders in the rodent family – the pebble-mound mouse creates artistic rock formations around the entrance of its communal den. These mounds can contain up to 50kg of pebbles –a lot of rock for a little mouse to shift!
From the beaches to the Red Centre, in just about any ecosystem, you’re bound to find a rodent that’s neatly adapted to its environment. From carnivores to herbivores, tree-dwellers to water rats, it’s these amazing and diverse traits that make rodents the unsung heroes of the Australian landscape.
High time, then, that these underappreciated overachievers had their turn in the spotlight as Australian Mammal of the Year!
The nominees for favourite rodent are:
Mitchell’s hopping mouse (Notomys mitchellii), semi-arid Southern Australia
Also known as the pankot, it is a bipedal rodent with large back legs and a long tail with a characteristic hopping mouse brush at the tip (which is thought to help balance when travelling at speed).
Stick-nest rat (Leporillus conditor), offshore islands in WA and SA and fenced reserves.
The greater stick-nest rat uses its sticky urine (called “amberat”) to glue its nests together. The amberat is so strong, the nests can last for thousands of years when sheltered from the elements under rock overhangs or caves.
Pookila (Pseudomys novaehollandiae), patchy distribution from Victoria to south-east Queensland, northeast Tasmania and Flinders Island.
Also known as the New Holland Mouse, they are micro engineers – despite their small size, they can create intricate burrow systems in sandy soils in which they nest during the day, raise their young, and stay safe during fire.
Dusky hopping mouse (Notomys fuscus), central Australia
The dusky hopping mouse is a social species that lives in stable colonies of up to five individuals in a burrow system.
Golden-backed tree rat (Mesembriomys macrurus), Western Australia
These rats’ most distinctive features are their dark eyes, the mohawk of golden hair that runs down their back, and their mega-long tail that looks like a giant paintbrush.
Desert Mouse (Pseudomys desertor), arid Australia
The desert mouse has a distinctive pale orange ring around its eyes, and predominantly eats leaves and shoots.
Bogul (Rattus fuscipes), coastal NSW, VIC, SA, WA and parts of QLD
Also known as the bush rat, these animals are territorial travel large distances to forage and mate during spring and summer. Males can traverse distances of up to a kilometre each night.
Rakali (Hydromys chrysogaster), all Australian states and territories
Also known as the Australian water rat, it has webbed feet for swimming, a face full of long whiskers for detecting aquatic food, and eyes and ears set high on the head so it can cruise semi-submerged through the water.
Smoky mouse (Pseudomys fumeus), southeastern Australia
As the name might suggest, this animal’s fur is fine, soft, pale-grey to bluish-grey, with a grey to white belly and a ring of dark hairs around the eye.
Broad-toothed rat (Mastacomys fuscus), South-eastern mainland Australia, Tasmania
Also known as tooarranas, they are well-known for making “ratways”, or tunnels through the grass and shrubs of their neighbourhood.
Eastern pebble-mound mouse (Pseudomys patrius), Queensland
It is known for building shallow burrows with entrances surrounded by mounds of pebbles which both collect dew and protect the burrow. It also lines the tunnel walls with pebbles for insulation and plugs smaller openings to the burrow with pebbles.
Black-footed tree rat (Mesembriomys gouldii), northern Australia
One of Australia’s largest rodents (weighing up to 880 grams), its nocturnal and forages for food in trees and on the ground but during the day shelters in large tree hollows.
Polling to determine the finalists of Australian Mammal of the Year is now closed. The Top Ten finalists will be announced on Monday 15 August and final voting for the Mammal of the Year will begin!
Originally published by Cosmos as Rollicking rodents – why our unique rats and mice deserve your vote
Isabelle Onley is a conservation biologist specialising in developing management strategies to future-proof species against climate change. She recently completed her PhD on the conservation, genetics and adaptive management of the greater stick-nest rat.
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