More than 1 billion animals believed dead in Australian wildfires

More than 1 billion animals are believed to have been killed in wildfires that have ravaged Australia since September, University of Sydney professor Chris Dickman told the Huffington Post in an update from his previous estimate of 480 million last week.

Why it matters: The fires have threatened Australia's wildlife, known for its rare animals and distinctive ecosystems. The environment was already imperiled by deforestation to support the country's growing agribusiness.

• The scale of the damage remains unclear because of a lack of access to the burned areas and because it is difficult to document animal deaths, but scientists say "it is clear that the devastation is immense," per the New York Times.
• Dickman explained that his earlier estimate was conservative and exclusive to the state of New South Wales — which he now estimates has more than 800 million dead animals alone.

What he's saying: "The original figure ― the 480 million ― was based on mammals, birds and reptiles for which we do have densities, and that figure now is a little bit out of date," Dickman told HuffPost.

• "Over a billion would be a very conservative figure," he said of the deaths continent-wide, adding that the toll has exceeded 1 billion "without any doubt at all."

Zoom in: Experts say thousands of kangaroos and koalas have been killed on Kangaroo Island, off the coast of South Australia, of which one-third has been destroyed, per the Times. They fear the worst for the island's subspecies of cockatoos, which only had a population of 300–370 before the fires.

• In a remote area of South Australia, aboriginal officials say they've approved a cull of up to 10,000 camels, as a drought has driven the thirsty animals to "threatening the APY [local government] communities and infrastructure," CNN reports.

Be smart: The estimated death toll is calculated by multiplying the number of estimated animals in a given area by the number of acres burned, according to Dickman.

Go deeper:

• New South Wales police arrest 24 suspects for arson related to wildfires
• In photos: Deadly wildfires rage across Australia
• Australia's deadly fires: What you need to know