Koalas – Dying

Science Diary: Koalas – Dying

Music

Melzer: I’m trying to take the skull off.

(Sounds of pulling desiccated carcass apart.)

Welcome to Pulse of the Planet’s Science Diaries, a glimpse of the world of science from the inside. We’re on St. Bees Island in Queensland, Australia, where biologist Alistair Melzer is examining the corpse of a dead koala.

Melzer: The whole carcass comes out – it’s just a shell. I’m retrieving the ear tags so we can confirm the identification later on.

Elsewhere in Australia, when koalas have been introduced to islands, the local population would spiral out of control, with koalas foraging on all the eucalyptus trees that’s their favorite food. Ultimately they’d eat all the available vegetation and then die out. But on St Bees Island, the population has remained constant.

Melzer: So, in theory, the population should be climbing steadily. Obviously, something must be limiting that population disease, predation, or some other mysterious factor. We don’t know.

But Melzer has begun to rule out some of these factors.

Melzer: We know that the traditional diseases that affect koalas are present on the island but are not causing overt disease, so we don’t know what’s happening here. I guess the most interesting finding so far is that a lot of animals disappear before they leave their parent. I can’t say that they die because they literally disappear. So, we know something is going on with these animals that’s not allowing full recruitment into the population, but we don’t know what yet. We have a real mystery, which we will now need to investigate over the next four years to identify this issue.

Pulse of the Planet is made possible in part by Virginia Tech, inventing the future through a hands-on approach to education and research. I’m Jim Metzner.

Koalas - Dying

What is keeping St. Bees Island's koala population in check?
Air Date:04/08/2015
Scientist:
Transcript:

Science Diary: Koalas - Dying

Music

Melzer: I'm trying to take the skull off.

(Sounds of pulling desiccated carcass apart.)

Welcome to Pulse of the Planet's Science Diaries, a glimpse of the world of science from the inside. We're on St. Bees Island in Queensland, Australia, where biologist Alistair Melzer is examining the corpse of a dead koala.

Melzer: The whole carcass comes out - it's just a shell. I'm retrieving the ear tags so we can confirm the identification later on.

Elsewhere in Australia, when koalas have been introduced to islands, the local population would spiral out of control, with koalas foraging on all the eucalyptus trees that's their favorite food. Ultimately they'd eat all the available vegetation and then die out. But on St Bees Island, the population has remained constant.

Melzer: So, in theory, the population should be climbing steadily. Obviously, something must be limiting that population disease, predation, or some other mysterious factor. We don't know.

But Melzer has begun to rule out some of these factors.

Melzer: We know that the traditional diseases that affect koalas are present on the island but are not causing overt disease, so we don't know what's happening here. I guess the most interesting finding so far is that a lot of animals disappear before they leave their parent. I can't say that they die because they literally disappear. So, we know something is going on with these animals that's not allowing full recruitment into the population, but we don't know what yet. We have a real mystery, which we will now need to investigate over the next four years to identify this issue.

Pulse of the Planet is made possible in part by Virginia Tech, inventing the future through a hands-on approach to education and research. I'm Jim Metzner.