Fossil records may save possums' skin

An Australian mountain pygmy possum. Photo / Supplied.

The mountain pygmy possum weighs 45g and lives above the snowline - but that may change.

Fossil records may hold the key to the survival of the mountain pygmy possum, one of Australia's most endangered species.

The tiny 45g marsupial is so rare that until 1966 scientists had known it only as a fossil, and believed it to be extinct.

Since one was found in a ski hut on Victoria's Mt Higginbotham they have been found to live only in small pockets of the Victorian and New South Wales alpine regions, above the snowline and with a rapidly declining total population of about 2000.

The furry grey possum, about the size of a mouse, is not coping well with the 21st century.

Males and females live separately in small communities, feeding on bogong moths, seeds and the fruit of the mountain plum, rambling bramble and snowbeard-heath to build up fat reserves.

In winter they hibernate, slowing the rate of their metabolism by about 98 per cent to survive, and in breeding season males migrate to the females' territory.

To keep them alive during this migration, tunnels were dug beneath roads.

National park borders have been extended to protect their habitat, and efforts are being made to defend food sources from invaders such as blackberry, and to control predation by foxes and feral cats.

Some areas are roped off during the snow season to protect hibernating possums.

But this is not enough and palaeontologist Professor Mike Archer, of the University of NSW's School of Biological, Earth and Environmental Sciences, believes prehistory may have the answer.

He said the fossil record showed that for at least 26 million years the possum's ancestors lived happily in rocky-floored rainforests, and that their ability to adapt to lowland forests again should be tested.

His plan to create a captive breeding colony to both provide a safety net for the vulnerable species and to test whether some gradually acclimatised possums could survive in lowland forests is gaining support.