“It’s a shocking number … it’s so big it’s almost difficult to comprehend,” leading ecologist and University of Sydney Professor Chris Dickman told SBS News on Wednesday.
“We haven’t really seen anything like this before.”
Professor Dickman presented the findings on Wednesday during a Senate inquiry into the unprecedented bushfires.
He said the knock-on effects of losing such a huge amount wildlife would be far-reaching.
"For the ecosystems in which these species occur, it may well be if species take a long time to recover their numbers - assuming that they do - it may mean a lot of the ecological processes that are otherwise important in sustaining forest function, will be lost," he said.
The earlier estimate of one billion animals was revised up as scientists came to grips with the disaster, Professor Dickman said.
"We are looking at a much larger area of burnt country now - it was 6.25 million hectares in January and it’s now about 11.5 million hectares," he said.
He also stressed the need for the government to heed climate predictions, especially when it came to protecting biodiversity.
"Although preparation was good in some respects, it wasn’t so good with respect to maintaining biodiversity," he said.
"I think we need to learn from that - find out which parts of the landscape are likely to burn, which parts of the landscapes have threatened species and other entities that we wish to conserve and make sure in our planning for the future that these really important components of biodiversity are factored in and conserved."
WWF Australia CEO Dermot O’Gorman said the findings rank the bushfire crisis as “one of the worst wildlife disasters in modern history”.
“It’s hard to think of another event anywhere in the world in living memory that has killed or displaced that many animals,” Mr O’Gorman said.