Animals killed in the fire includes mammals such as koalas, and reptiles such as skinks (lizards) and frogs.
As the number of fires in Queensland, Victoria, and New South Wales continues to rise, the death toll of animals is likely to increase.
Unprecedented continent-wide bushfires
As of Jan. 2, 2020, 110 fires are still raging across NSW with over 50 uncontained.
While a number of Australia's native flora and fauna are reliant on fire to reproduce and bushfires occur seasonally, the scale of bushfire this time is unprecedented and almost continent-wide.
Australia has lost an area of more than three million hectares to the fire thus far and this is much more devastating than the usual area of 280, 000 hectares burnt in a season in the past few years, according to the NSW Rural Fire Service.
Scientists cited record-breaking drought as one of the key reasons for this devastating fire.
480 million animals suspected to have perished
The deadly blaze has destroyed homes of animals and some of them could not outrun the fire in time, especially slow-moving animals such as the koalas.
Of all animals, koalas are affected the most as they are usually found on eucalyptus trees which contain oil that vaporises in the heat and makes the plant highly flammable.
Other animals that are threatened by the fire include wombats and kangaroos.
Speaking to the Daily Mail, an ecologist from the University of Sydney, Chris Dickman, estimated that about 480 million mammals, birds, and reptiles have been killed, both directly and indirectly, by the flames since September 2019.
A non-profit conservation, Science for Wildlife, also added that there were no protocols put in place to save the koala populations from such disasters.
"We're getting a lot of lessons out of this and it's just showing how unprepared we are," said Science for Wildlife executive director, Kellie Leigh.
This resulted in wildlife carers risking their lives to save the animals without proper safety measures.
"We are not seeing the amount of animals coming into care or needing rescuing that we would normally anticipate," Price, who works with wildlife rescue group WIRES, told AFP. "We think a lot perished in the fires."
Haunting images of koalas with singed fur, possums with burnt paws or countless charred kangaroo carcasses have flashed around the world and have come to symbolise a nation and an environment buckling under the weight of a crisis fuelled by climate change.
The populations of less visible creatures, such as frogs, insects, invertebrates and reptiles, are also expected to have been devastated.
Experts warn that even those animals that survive face a perilous fight to stay alive.
"A lot of the animals die after the fire because they have a lack of food and lack of shelter," Mathew Crowther of the University of Sydney told AFP.
"They could get eaten by other animals, or they can't get enough food for themselves."
In Victoria state, where the fire season is still in its early stages, veterinary surgeons said they have come across koalas, birds, wallabies and possums suffering from not just burns, but respiratory problems.
"Many are having to be humanely euthanised, but some are able to be saved, with a handful being returned to the remaining habitat, and three brought into care ... so far," a spokeswoman for Zoos Victoria said.
University of Sydney professor Chris Dickman said his estimate of more than one billion animals killed was "highly conservative".
"We're probably looking at what climate change may look like for other parts of the world in the first stages in Australia at the moment."
When the fires abate, Crowther said some populations might become so small they could be taken into captivity to try to save their species.
Some parts of the bush will take decades to recover and experts say substantial investment may be needed to restore habitats if animals like Chance are to have another shot at survival.