Humans can be such a problem for native wildlife. We build roads over wildlife trails so we can zoom down to the ski fields, not worrying about the native casualties that get squashed along the way. But humans can also be the solution - as we have been with the endangered Mountain Pygmy-possum (Burramys parvus). There are possibly only a few thousand of these amazing animals left in the wild. They live in the snow-covered alpine and subalpine regions of New South Wales and Victoria, above 1400 metres. They are the only Australian mammals found here and nowhere else.
For most of the year male and female possums live separate lives scurrying among rook crevices, boulder fields and alpine shrubs. Adult females live in the best locations on rocky slopes. Males live further down the hill. Come breeding time, these males make the hazardous trek across the roadways, attempting to avoid all the human-made obstacles in their way. Only when they have made it to the other side of the roadway can they consider scurrying up the hills to find the waiting females. It’s a wonder they have any energy to mate at all!
When the ski runs are covered in snow they are compacted by all the skiing. Luckily humans have realised the problem. They haven't diverted the roadways or ski runs but they have done the next best thing. They have constructed rocky tunnels under the roadway and under some of the ski runs, so love-struck male possums can migrate between residences with relative safety. Once breeding season is over and the young are weaned, it is back down the hill for the males, battling with mechanical contraptions again, to the safety of their home range.
The Mountain Pygmy-possum is often mistaken for a mouse. You don’t want to kill a native animal, so how do you tell the difference? The possum’s second and third toes are joined, unlike a mouse’s, but the most obvious difference is its curly tail. This tail has an essential task. It is prehensile, which means it can grasp things, like the thin-stemmed grasses that the possum uses for nest building. The possum’s sharp premolar teeth on the side of the mouth are large and grooved, just right for cutting these grasses. They are also great for eating hard-shelled seeds and insects.
More than half of the possum's diet is invertebrate such as beetles and caterpillars. It especially likes the energy-rich Bogong Moth (Agrotis infusa), which is the main part of its diet during spring and summer.
The Bogong Moth is a sweet morsel for the possum. In spring, this small brown moth migrates annually from its breeding grounds on the western slopes and plains and spends summer dormant (or resting) among rocks and boulders of the alpine peaks. Most moths are found on the mountain peaks and this is where the possums must travel to get their food.
It also eats fruits and seeds, especially from the Mountain Plum Pine. This plant is very sensitive to fire and can take decades to recover from a bushfire. In 2011 a large bushfire in Kosciuszko National Park caused problems for the possum’s diet and also affected much of the plant cover that it uses to hide from predators.
During winter the possum hibernates, going into a state of inactivity or torpor. It slows down its breathing and heartbeat, and reduces its body temperature to 2 degrees Celsius. That’s how it saves energy: This requires a good cover of insulating snow, at least 1 metre. The possum is torpid for up to 20 days when it is very cold. Then it wakes for less than a day, maybe eating from its storage supplies, before once again resuming its ‘sleep’. This cycle goes on for up to seven months. The Mountain Pygmy-possum is the only marsupial that hibernates
Being a fat Mountain Pygmy-possum is very important. A fat possum has lots of stored energy which will sustain them through the winter food shortage. In springtime, after hibernation, the possum might weigh about 40 grams but by wintertime they might weigh more than 80 grams. This possum is also a great hoarder. During winter it uses not only the energy stored in its body, but it can also eat from its hidden store of seeds and nuts. It is the only known Australian marsupial to do this.
◆ Australiana by Ty Buchanan ◆
Australian Blog
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