Nearly 3 billion koalas, kangaroos and other native Australian animals were killed or displaced by bushfires in 2019 and 2020, according to a study by the World Wide Fund for Nature (WWF), triple the organization's earlier estimates.

Some 143 million mammals, 2.46 billion reptiles, 180 million birds and 51 million frogs were impacted by the country's worst bushfires in decades, the WWF said on Tuesday.

The fires destroyed over 11 million hectares (37 million acres) across the Australian southeast, equal to about half the area of the United Kingdom. When they were blazing, the WWF estimated the number of affected animals at 1.25 billion.