Give a rats! How to identify South Australia's native rodents

The word ‘rat’ might give you an instant ‘ick’ or conjure images of pesky feral brown and black rats.

But did you know these aren’t the only kinds of rats you may encounter in SA? There are a range of native rodents you may never have heard of, and they’re all pretty interesting if we do say so ourselves!

It’s important to be aware of the different kinds of rodents we share our state with as native animals are protected under the National Parks and Wildlife Act 1972 – meaning you can’t employ the same trapping/baiting approach you may use for feral rats and mice.

To ensure our native rodent species are secure in the landscape, we all need to play our part in protecting them for the long-term.

1. Swamp rat

The Australian swamp rat, also known as the eastern swamp rat, is a real cutie, with black-brown fur and very small ears.

Preferring coastal and marshy areas, swamp rats have been recorded across the Fleurieu Peninsula, Kangaroo Island and the South East, so if you live there, there’s a chance you may come across one of these critters in your backyard.

They’re herbivores and have been known to move into veggie gardens (a buffet breakfast, if you will).  

A definitive sign that you may have swamp rats is if you see signs of their extensive ‘tunnels’ or ‘runways’ through thick, long grass and vegetation, which they use to get from burrow to burrow.

Unfortunately, these critters are at risk and are listed as rare under the National Park and Wildlife Act 1972.

If you think you may be sharing your backyard, or your vegetable patch, with a swamp rat, try:  

• Keeping the area around your vegetable patch free of other vegetation and maintain short grass. Swamp rats prefer moving through covered areas, like tunnels, so by creating an open, exposed space, you reduce the chances of them building runways and make the area less appealing to them.
• Install wire mesh or shade cloth around your veggie patch to provide a physical barrier, bury it to a depth of 200mm to prevent swamp rats digging under it.
• Consider raised vegetable beds. Swamp rats are primarily ground dwelling rats rather than climbers, so raising the height of the bed can deter them from entering your patch.

2. Rakali

While the rakali is a native rodent, it is often thought of as the Australian equivalent of otters.

Also known as a water rat, rakali live in burrows along watercourses and riverbanks, and can measure up to half a metre long from nose to tail.

Rakali are adept at swimming, with webbed feet and thick, white-tipped tails that serve as rudders.

They eat small fish, insects, frogs, crustaceans, bird eggs and even mice, making them one of Australia’s only carnivorous rats!

They have soft, water-resistant fur, which is dark brown on their heads and backs and creamy on their bellies. There was once a water rat fur industry in Australia.

You can find rakali in any permanent bodies of water and their presence is a sign of a healthy waterway. While they’re nocturnal and known to be quite shy, you may be lucky enough to spot one in the River Torrens!

3. Bush rat

Bush rats are one of the more common native rodents in Australia, found in NSW, VIC, WA, parts of QLD and here in SA.

They have a rounded head and pointed nose, large round ears, and chisled teeth.

While these rats look quite similar to other native rodents, such as the swamp rat, their tails are a pinky-brown with a distinctive ringed appearance.

4. Greater stick-nest rat

The greater stick-nest rat was once widespread across arid areas of southern Australia, but by the 1930s they were exctinct in the willd on the mainland, primarily due to introduced predators.

While you're unlikely to com across these rats in day-to-day life, they are a very important species to South Australia.

The only naturally-occurring wild population of greater stick-nest rats is located on the Franklin Islands off the coast of Ceduna on Eyre Peninsula, in the Nuyts Archipelago.

Free from the threat of feral cats and foxes, this population has became the foundation of conservation efforts to reintroduce the species to predator-free areas on the mainland.

Other islands, with successful populations include St Peter Island and Reevesby Island, also off the coast of Eyre Peninsula, as well as Salutation Island off the coast of Western Australia.

They’re also listed as vulnerable under the National Parks and Wildlife Act 1972.

About the size of small rabbits, they have grey-brown fur and rounded heads and ears.

They’re herbivores and feed on fresh plants, fruits and seeds.

Research has also shown that these rodents are partial to one of our worst invasive plants, the African boxthorn.

They build communal nests up to one metre high and 3 metres wide!

These nests are constructed with sticks, grasses and leaves, and are sometimes glued together with a mixture of faeces and urine that forms a resin-like material.

Nests like these can only survive when made under shelter, as the resin is soluble in water.

The nest construction is added to, or modified by, successive generations and may house communities of 10 to 20 rats.

Living with our native rats

Think you have rats in your house or backyard? Before you set a trap – stop! If there’s a chance your visitor might be native, you won’t be able to bait or trap it.

Instead, consider these tips:

• Remove potential food sources like pet food or fallen fruit
• Keep outside areas tidy and clear up woodpiles and other debris
• Trim overgrown plants and shrubs near your house.
• Block entry points to your house.

Other tips to live with, and support our, native rodents:

• Be a responsible pet owner – keep your cats inside and don’t take any pets into national parks.
• Learn more and support initiatives like Arid Recovery reintroducing species like the greater stick-nest rat to predator free havens on the mainland.
• Think twice before using feral rodent baits around your house or garden that can be harmful to wildlife. If they are a necessity, be sure to choose baits with first generation active ingredients, which have lower risks of secondary poisoning and use them in tamper-resistant bait stations to protect non-target animals.

Other tips to tell a native rat from a feral rat

• Native rats generally have tails shorter than their bodies, while both black and brown rats have tails significantly longer than their bodies.
• Native rats are generally shy and skittish, whereas black and brown rats are often quite bold and are regularly seen out and about.

Species that get confused for rodents

South Australia is home to many cute and quirky marsupials, some of which can even get confused for rats or mice.

These include:

• Dunnarts – such as the vulnerable sandhill dunnart (found in only a few locations in SA), and the endangered Kangaroo Island dunnart (who’s habitat was dramatically affected by the 2019-20 bushfires).
• Yellow-footed antechinus, be sure to check out how to tell if you’ve got a pesky mouse or a native antechinus in your house

Have you got possums visiting too? Or how about bats? Or blue-tongue lizards? Check out our stories to find out what to do:

• What to do if there’s a possum in your roof
• What to do if there’s a bat in your house
• What to do if there’s a blue-tongue lizard in your backyard