Professors at the University of Sydney estimate that close to half-a-billion animals have died since September 2019 as a result of uncontrollable fires in Australia. The figure covers a wide range of wildlife, including reptiles, mammals, and birds.

"In the longer term, the rebuilding of populations of many native species is going to be the issue," professor Chris Dickman told Seven News in Australia.

The bushfires started in the Yorke Peninsula, in the southern tip of Australia, at the end of November and have spread rapidly across the island since. As revelers celebrated the new year around the world, a cloud of smoke hung over Sydney on New Year's Day as Australians fought to put out fires that have engulfed the nation for over a month.

Koalas have been especially hurt by the fires, with around 8,000 having perished, which is more than one-third of the koala population in mid-north coast of New South Wales. Videos of desperate koalas approaching people in search of water have circulated during the past week on Twitter.

In record heat Australia and South Australia, where temperature have risen to 40 degrees, koalas approached cyclists on the road to seek water. pic.twitter.com/DvW84gbaRq — Akki (@akkitwts) December 28, 2019

Watch these firefighters stop to give a thirsty koala water while fighting brushfires 🐨 #AustraliaBurning pic.twitter.com/DrZMnAQQFP — NowThis (@nowthisnews) January 2, 2020

"There is such a big area now that is still on fire and still burning that we will probably never find the bodies," ecologist Mark Graham told Metro.

Footage from Monaro, New South Wales, showed throngs of kangaroos hopping across the desert as bushfires expanded into the area.

Heartbreaking footage of kangaroos fleeing has been captured in Monaro, NSW, as bushfires close in.



For more fire updates: https://t.co/m3qKpIZsu5 pic.twitter.com/Jo6MDtuygC — news.com.au (@newscomauHQ) December 31, 2019

Citizens on the ground described the situation as "catastrophic," and videos posted to Twitter show people fleeing on boats against a dark red sky of fire and ash. More than 10,000 people have lost homes in New South Wales, which includes the city of Sydney.

‘F**k I’ve never seen anything like it,’ this man has described the scenes in Mallacoota, Victoria after he was forced to escape a huge bushfire by boat. pic.twitter.com/sZuZkZEnaa — SBS News (@SBSNews) December 31, 2019

"My last day of the decade felt like the apocalypse," tweeted Panos Pictures photojournalist Matthew Abbott. "Been covering the Australian bushfires for the last 6 weeks, but haven’t seen anything like yesterdays fire that decimated the town of Conjola, NSW."