The forest is full of mysteries. Unknowns and certainties. Things that go bump in the night. Even the most seasoned camper will tell you stories of when a rustle in the bushes, or a strange and unintelligible sound from the shadows had them scampering back to the firelight.
I remember one night a decade ago, when the screech of an owl had me veritably shaking in my sleeping bag. It’s worse when the source of the interruption is unknown. Fuelled by scary movie memories, the imagination can quickly turn a pleasant weekend camping into a nervous system nightmare.
This could have well been the case for me recently. Camping in the forest near Chichester, I was woken by a deep guttural growling and grunting, a kind of cross between a chainsaw and the death rattle of a bison. The noise continued in outrageously loud bursts, seemingly getting closer and more urgent. To the nature illiterate, I can imagine this would be terrifying beyond belief. I smiled, trying to marry the sound with the soft furry creature I knew it to be, hanging out in a tree somewhere above me. My night monster was none other than a koala.
It may come as a surprise to some that the sleepy cuddly koala morphs into a noisy aggressive beast during breeding season when the amorous males start defending their territory and advertising their prowess to the gals. Known as a ‘bellow’, the loud snoring-belching call of the male koala can often be heard several kilometres away, and most often at night.
Scientists have found the bellows are used by male koalas as a way to boast about their body size and make them sound significantly larger than their size. The research also found that the low, rasping bellows are the result of a ‘descended larynx’, something previously thought to be a human-only feature, enabling a variety of sounds.
If you can’t hear them, you may have the pleasure of sniffing them out instead. The apparently intoxicating smell is a mix of urine and the pungent musky scent gland on the male’s chest, which they rub vigorously against branches to mark territory as they climb.
The action can sometimes get physical too. If a dominant koala spots another male hanging out in his territory, he will first try to scare off the intruder with a bellow. If this doesn't work, the big guy moves in for the attack, with koalas known to be have even been pulled right out of a tree by their adversary during combat. Smelly, aggressive, noisy and amorous. Doesn’t sound anything like adolescent males!
In the morning I scanned the canopy, but the noisy grey bums had either disappeared or were well camouflaged. Arriving home, I opened to a news report headlining the predicted decline in koala numbers due to climate change in coming years. Although potentially goose bump raising, it would be silent and sad forest without this quintessentially Australian summer sound.