As almost 500 million animals have died since the Australian bushfires began, there are real concerns that entire species of plants and animals have been wiped out.
Ecologists from the University of Sydney estimate 480 million mammals, birds and reptiles have been lost since September, reports The New Zealand Herald.
Following the devastating fires, which ripped through Victoria and the southern coast of New South Wales over the past couple of days, that figure is likely to soar.
The fires have left several people dead or unaccounted for, razing scores of homes and leaving thousands stranded.
More than 130 fires were raging across New South Wales and Victoria, with millions of hectares of the national park already burnt on Wednesday, January 1.
Harrowing scenes of kangaroos fleeing walls of fire, charred bodies of koalas and cockatoos falling dead out of trees have horrified the world as it tries to take in the scale of the unfolding disaster.
Koalas have been among the hardest hit of Australia's native animals because they are slow moving and only eat leaves from the eucalyptus tree – which are filled with oil, making them highly flammable.
Up to 8,000 – a third of the entire koala population of the New South Wales mid-north coast – are believed to have been killed in less than four months.
There are significant koala populations in others states affected by fire – such as Victoria and South Australia – but no figures yet on how many have been lost.
"The fires have burned so hot and so fast that there has been significant mortality of animals in the trees, but there is such a big area now that is still on fire and still burning that we will probably never find the bodies," Nature Conservation Council ecologist Mark Graham told the Australian parliament.
"[Koalas] really have no capacity to move fast enough to get away as the flames jumped from treetop to treetop," he said.
Graham was addressing the New South Wales upper house inquiry, which last month held an urgent hearing into the state's koala population in the wake of "unprecedented" destruction.
Science for Wildlife Executive Director Dr Kellie Leigh told the hearing there were no resources or planning in place to save koala populations threatened by fire in the Blue Mountains.
"We are getting a lot of lessons out of this and it's just showing how unprepared we are," Dr Leigh said, adding, "There's no procedures or protocols in place – even wildlife carers don't have protocols for when they can go in after the fire."
Stand Up for Nature, an alliance of 13 organisations, is calling for an immediate halt on logging of native forests in New South Wales until the impacts of the catastrophic bushfires are understood.
"The impact on many species has been extreme and is ongoing. The full scale of wildlife losses will probably never be known, but they will surely number in the millions," it warned in a letter to New South Wales Premier Gladys Berejiklian.
"These unprecedented fires have jeopardised the long-term viability of threatened species populations and forest ecosystems in several areas."
The alliance acknowledged a moratorium could have impacts on native forest timber industry workers and their communities.
"We therefore call on the government to ensure logging industry workers are supported during this process, either with alternative employment options, financial assistance or other worthwhile alternatives. We stand ready to engage constructively with the industry and government to achieve this goal."
Environment Minister Sussan Ley said true animal death figures would not be known until "the fires have calmed down and a proper assessment can be made."
The saviour staff of Mogo zoo
Australia's largest collection of primates, along with zebras, rhinos and giraffes are housed in Mogo Zoo, situated in New South Wales.
The zoo keepers managed to protect all 200 animals from harm when the bushfire started.
Most of the animals were sheltered at the site; however, monkeys, pandas and even a tiger were temporary lodgers at one keeper's home.
An evacuation order was made for the New South Wales area where the zoo is located, but staff decided to stay to protect their animals.
Chad Staples, director of the zoo said the situation had been "apocalyptic" and that it "felt like Armageddon."
He said the zoo only survived because there had been a precise plan in place: first the zoo keepers moved everything flammable from the area and then turned to the animals themselves.
The larger ones like the lions, tigers and orangutans were moved into secured night enclosures to keep them safe and calm, but the smaller ones needed extra shelter.
Staples decided to simply have them taken to his own house.
"Right now, in my house there's animals of all descriptions in all the different rooms, that are there safe and protected, not a single animal lost," Staples said.
Sara Ang from the wildlife park told BBC 5 Live radio that "some of the smaller monkeys had to be moved to the house, the red panda is in the house and there's a tiger in the back area of the house.
"All the animals that needed to be moved indoors have been moved indoors," and hence are safe from the fire.
Staples explained that these were the only animals that suffered from stress – not from the fires but due to the rush of keepers and vehicles moving around to fight the flames. Describing how his team worked for hours and throughout the night, he said the park would have been lost to the fire had it not been for the staff's heroic efforts to save it.
The zoo's survival is a positive development after a devastating week along Australia's eastern coast.
Fires have also destroyed more than 200 homes, leaving thousands of people facing an uncertain future.