The Pros And Cons Of Possums In Your Roof

Image: iStock

You’re drifting off to sleep when, suddenly, there’s a bump and a thump and an unearthly shriek. But never fear, if your home is making these noises you probably don’t have ghosts, but a family of common brushtail possums. Researchers have documented 18 different brushtail possum sounds. These include “grunting, growling, hissing, screeching, clicking and teeth-chattering calls, many of which would not be out of place on a horror movie soundtrack”.

Common brushtail possums (Trichosurus vulpecula) live across much of suburban Australia. Although often associated with bushland environments and commonly considered a tree-dweller, these adaptable creatures are also highly attracted to human houses.

The biggest hidden housemate?

Despite being the same size as a domestic cat, these lively, nocturnal marsupials frequently make their dens in the ceiling and wall cavities of homes. In fact, one study of possums in urban Tasmania found that 87% of their visits to dens were associated with buildings (mostly older houses), while 45% of den visits were to roof cavities.

These hidden animals make themselves known to their human housemates as they run across the ceiling. A Sydney study found that as many as 67% of people whose properties were visited by possums heard possum activity on or in roof cavities, while 58% reported possums living in these spaces.

Possums in the city

At the time of European arrival, common brushtail possums were abundant across mainland Australia and Tasmania. However, intensive hunting for a burgeoning fur trade in the 19th and early 20th centuries led to a drastic decline in possum numbers. Since the end of hunting, habitat degradation and fragmentation, fires and fox predation have put further pressure on possum populations. In contrast, they appear to be flourishing in our cities.

Common brushtail possums are territorial creatures, usually sleeping alone during the day in dens in tree hollows, rock piles or logs. Dens are often in limited supply in the bush and possums will compete for nesting sites, sometimes fighting to the death. In contrast, suburbia provides an abundance of potential nesting spaces.

In fact, urban possums seem to prefer living in human-built structures, even when hollow trees are available. A single roof can provide a home for many cohabiting possums, although disputes among roommates may become raucous.

Another reason that brushtail possums have adapted so successfully to our cities is their generalised diet. Unlike specialised eucalypt feeders like the koala, brushtail possums eat the leaves, flowers and fruit of a range of native and exotic plants, as well as Eucalyptus leaves. They also sometimes eat insects and bird eggs.

Thus suburban gardens, with their abundance of fruit trees, roses and vegie patches, provide a “possum supermarket”, conveniently offering a diverse array of tasty, nutritious foods year round – much to the frustration of many gardeners!

In a study in eucalypt woodlands in north Queensland, Jane and her colleagues showed that female possums with access to the greatest amounts of available protein within their home ranges were more likely to breed twice, rather than just once per year.

Eucalypts are generally a poor source of protein and this is likely to limit populations of possums in natural bushland. However, given the abundance of high-quality food sources and limitless den sites in urban environments, it is not surprising that common brushtail possums seem to thrive there.

A possum in the roof!

People who share their homes with possums describe hearing them walking around the roof cavity. Emma’s research heard residents speak about the “thump, thump, thump” of possums walking across the ceiling. Others described being jolted awake at dawn to crashing and scraping sounds, and a feeling that someone was in the house. Some people admitted thinking their house was haunted, a feeling that was triggered by night-time noises coming from hidden spaces.

Image: play4smee, Flickr

Many people enjoy living with possums, because they feel like it connects them to a time before Australia was urbanised. Some people also value personal connections with possums, becoming familiar with the individuals that share their garden – even giving them names and pointing them out to visitors.

However, people also often describe possums as a pest. They complain about the noise and damage that possums can cause. Damage to ceiling cavities, urine stains and odours in the ceiling are reported, and some people experience possums dying in the ceiling. These rotting bodies can be overwhelmingly smelly and extremely difficult to find.

It is interesting that many people both value possums and find them to be a pest. This is evidence of the complicated relationship that we have with native animals that live inside our homes. We enjoy their wildness, but are also challenged by the way that they make our homes a little bit less human and a little bit closer to nature.

Living well with common brushtail possums

Despite the fact that some people are less keen on house-sharing with possums, they are protected under the wildlife acts of most states in Australia. Although these laws vary, they generally require that residents seek a licence before trapping or moving a possum.

In New South Wales the relevant law is the National Parks and Wildlife Act 1974. If a possum is living in your ceiling, in NSW you can apply to the Office of Environment and Heritage (OEH) for a licence to trap it. Possums must be trapped humanely and released on the property where they were found within 150 m of the place where they were caught.

Note, however: possums moved outside of their home range typically die. They are also usually replaced within four weeks by another possum that moves into their territory.

The OEH suggests that people live alongside possums that share their garden, explaining that “if you encourage a possum to stay around and claim your yard as its territory, other possums will be discouraged from taking up residence”. The OEH also recommends installing nest boxes in trees away from the house to discourage possums from nesting in roofs, and carrying out repairs to close up any holes after possums are removed.

Wildlife protection laws mean that common brushtail possums have a right to live in urban Australia. This means that we need to learn to live well together.

Emma Power, Senior Research Fellow, Geography and Urban Studies, Western Sydney University and Jane DeGabriel, Research Fellow in Ecology, Hawkesbury Institute for the Environment, Western Sydney University

This article was originally published on The Conversation.


    Nice article. Those that consider possums to be pests really should be more tolerant and empathetic. These are animals that are just trying to survive the best way they know how. There are services that can possum proof your house and put up some possum boxes, and it's not a difficult task to do yourself if you're vaguely handy. They are also sweet and benign animals that are easy to befriend and get along with. This expectation that nature should bow before us and make way for the all powerful humans is arrogant and selfish. We have already driven so many species to extinction and are responsible for the ongoing suffering of so many others. Here is an opportunity to live in harmony with an animal that means us no harm whatsoever, and in fact can become a nice friend if you can take a moment to try and look at the world from their perspective and be a little understanding. If you are so affronted by an animal eating your roses, then I'm sorry but I think you need to put things into perspective and reorder your priorities. Instead of trying to bend nature to your will to serve your peculiar aesthetic tastes, try living in harmony with nature and appreciate it's inherent aesthetics, or modify it in a way that can be enjoyed by both you and your potential animal friends. Everything with nicer when enjoyed with others.

      In New Zealand our only native mammal is the bat.
      Possums wreck our beloved native birds.
      We're not intolerant, we have our priorities exactly right for our biome.

        Unless I'm mistaken this is an Australian article...

          Australia has 86 endangered species and my argument applies just as well to their habitats.
          Nature sometimes needs custodians, not harmony.

            You're argument does not apply to Australia with respect to possums, which is the topic of this article. My comments relate specifically to possums and people's intolerance of them in urban environments in Australia. In Australia possums are not invasive or displacing other native species. So actually no, your "argument" does not apply, you are making a completely separate point that is not relevant to the article or my comments.

              So, you used 240 words merely to advocate that people ought be nice to urban Australian possums in Australia?
              I apologize for imagining you had some wider point. :)

                No worries, reading comprehension isn't everyone's strong suit.

                  I understood your post perfectly, despite its lack of structure.

                  Where I went wrong was inferring (from your lack of concision) that you also intended your readers to derive a less trivial point.

                  In discussion, there's a virtue known as the 'principle of charity'. Sometimes, unfortunately, extending said charity is to overestimate the target of said charity.

                  Last edited 09/08/16 12:20 pm

    I remember as a little kid my grandparents house had a possum living in it. They had a hole in the bathroom ceiling (from an old wood heater that was removed) and everytime you'd take a bath the possum would stick it's head out and watch.

    We also had them at my parents house on acreage and they got quite domesticated, coming to the back verandah and eating fruit we'd put out. Though we never tried to hand feed them or pat them.

    Currently I get nightly rooftop visits from the little buggers because they use the power line to cross the road. So everynight "bounce bounce bounce" across my tin roof. Sets the dog off as well >_<

    Still wouldn't wish them gone though. A little bit of noise is a fair trade off to have the furry little buggers around.

    My sisters old place had possums and they were pretty chill, enough to come up and gently take a slice of apple out of your hand although when i house sat would get freaked out when they would run across the roof in the middle of the night.

    We had them in the roof (actually their nest was in the ceiling above our bed) and I guess we could live with it as we couldn't find where they were getting in/out of the roof space, but the final straw (at least for Mrs Magani) came when, during one of the nightly 'Possum Olympics', one of the furry friends stepped on the fan/heater/light fitting shroud in the en-suite and sent it crashing onto the toilet at 2am.

    As we didn't want to pay $$$ (lots) for the local possum man to move it the 100m or so (I figured the possum would beat him back) and we'd rather they left of their own accord, a bit of research came up with the following:-

    a - They don't like light when they're sleeping in the daytime
    b - They don't like loud noise (ditto), and
    c - They don't like strong unnatural (to them) smells.

    We decided on a pair of Halogen work lights in the ceiling as well as spreading naphthalene balls around the roof space. We decided *against* playing Iron Maiden or Def Leppard at high volumes during the day!

    Result: After 3 days, no possums, and presumably because of the naphthalene balls' residual smell, no new ones moved in. However, they still transit across our roof each night, but no longer eat the herbs out of Mrs Magani's garden. Once they'd gone, we also had the roof repainted and sealed against further nightly marauders.

    Last edited 23/07/16 9:45 pm

    I'll never forget the time one died in the ceiling of a place I was renting many years ago. Came home after a weekend away to find it had bled through the ceiling onto my lounge suite. At first I thought when did I spill wine on my couch?....then I saw the large gelatinous patch on the ceiling...took me over two weeks to get the landlord to sort it out. Didn't help that the place didn't have a man hole, was a tin roof and the middle of summer. Fun times.

      My grandparents had a fireplace removed, but they didn't cap the top. A possum got in the chimney, couldn't get out, and died. The smell was god awful.

    We have brushtails and ringtails, and a very healthy python!

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