music; ambience jungle, Koalas
â€œYouâ€™re really listening to a soundscape that has come through from prehistoric times.â€
Alistair Melzer studies the behavior of Koalas on St. Bees Island, off the coast of Queensland, Australia. Welcome to Pulse of the Planetâ€™s Science Diaries, a glimpse of the world of science from the inside. This month a look back and an update on some of our favorite stories.
â€œOne of the first things that strikes you about living with a population of Koalas in a relatively undisturbed part of the Australian bush is the sound. The Australian forest is dynamic at night. And if youâ€™re living in a Koala population, you get to hear sounds that have been trumpeted across the Australian landscape for millions of years.â€
â€œSo, in the breeding season for Koalas, which is from October through to January or February, the male Koalas that are quite territorial are calling. One Koala will call, another Koala will respond, and then other Koalas will call, and thereâ€™ll be this chorus of calls thatâ€™ll run around the landscape.â€
In the 1920s and 30s, Koalas were introduced to islands off Australiaâ€™s mainland, partly as an attraction for tourists.
â€œThe question weâ€™ve got is that where Koalas have been introduced to islands in other parts of Australia, theyâ€™ve become pests. They reach plague proportions. They kill the trees that they live on and cause a lot of damage. Where Koalas have been introduced to islands in Queenslandthatâ€™s in the tropicsthese populations donâ€™t run out of control.â€
Despite stable populations, on St. Bees Island, young Koalas are mysteriously disappearing. Alistair Melzer now theorizes that theyâ€™re being displaced during the confusion of the mating season. Another possibility is that mothers are weaning their young too early.
Pulse of the Planetâ€™s Science Diaries is made possible by the National Science Foundation. Iâ€™m Jim Metzner.