CANBERRA, Australia (Reuters) -- Female koalas are being given contraception in the Australian state of Victoria because the population is eating itself out of house and home.
Koalas are in danger of over-breeding themselves towards extinction in some parts of Australia.
Rampant koalas put on the pill
Parks Victoria is planning to inject a small tube containing the same hormones as the contraceptive pill under the skin of around 3,000 wild female koalas in the Mount Eccles National Park which is 300 km (186 miles) southwest of Melbourne.
Sally Troy, Parks Victoria's research manager, said on Wednesday that the koala population had to be brought under control because their staple food, the manna gum in the Mount Eccles National Park, was close to depletion.
"The forest is continuing to decline as the animals just keep eating and breeding," Troy told Reuters.
"We're concerned there is a really high risk that we will get a population crash in the next five years -- that is the trees die and thousands of koalas starve to death," Troy said.
"We have found that relocation and surgical sterilisation hasn't worked that well, so now we're shifting to a more humane, large scale option which is basically putting them on the pill."
Troy said contraceptive implants, which can be inserted on-the-spot without the use of any anaesthetic and last for about five years, have previously been used in zoos on kangaroos and other marsupials, but never on wild animals.
Koalas can live for up to 18 years and may produce between eight and 11 offspring during their lifetime. They generally start breeding when they are around two-years-old.
The Australian Koala Foundation says there are around 100,000 of the creatures in the country.
"There's not a lot of predator pressure on these animals anymore...They are also protected species so the numbers in some areas have just grown steadily," Troy said.
She said the Parks Victoria operation to catch and inject the contraception tubes into the koalas would begin late next year and was likely to take two years.