In a grim video posted on Twitter, a man drives into the fire-ravaged town of Batlow in the Australian state of New South Wales. Both sides of the road are covered with ash and lingering smoke. They're also littered with the charred remains of animals killed in wildfires that have ripped through the region.
The blazes, which have been burning across Australia for months, have razed homes and wiped out entire towns. Across Australia, nearly 18 million acres of land have been burned — much of it bushland, forests and national parks, home to the country's beloved and unique wildlife.
Nearly half a billion animals have been affected by the fires in New South Wales (NSW) alone, with millions potentially dead, according to ecologists at the University of Sydney. That figure includes birds, reptiles and mammals, except bats. It also excludes insects and frogs, meaning the true number is likely much higher.
The total number of animals affected nationwide could be as high as a billion, according to Christopher Dickman, the University of Sydney ecologist who led the report.
Fires are nothing new in Australia, but they have been growing more intense and becoming more destructive in recent years, a problem that has been exacerbated by climate change. And animals have been on the front lines. Australia has the highest rate of species loss of any area in the world, and researchers fear that rate could increase as the fire disaster continues.
"The scale of these fires is unprecedented," said Dieter Hochuli, an environmental sciences professor at the University of Sydney. "There are substantial concerns about the capacity of these (ecosystems) to rebound from the fires."
Flames, food and predators
The team at the University of Sydney came to its conclusion by using estimates of NSW mammal population density in 2007 in order to estimate how many animals have been affected by the 4.9 million hectares (12.1 million acres) that have been set alight in the state this fire season.
It's a pretty good estimate, Hochuli said, but until the fires stop, they have no way of surveying exactly how many animals have died. And since the density figures excluded some species of bats and frogs, "the true loss of animal life is likely to be much higher than 480 million," said a statement from the university.
Some animals, like koalas and kangaroos, are primarily killed directly by the fires — for instance, by being incinerated in flames or choking on smoke. Nearly a third of all koalas in NSW have died and about a third of their habitat has been destroyed, federal environment minister Sussan Ley said in December.
Photos from the ground show koalas with singed fur, raw patches of burnt flesh and blistered paws. Even if they are rescued and treated, sometimes their injuries are simply too extensive to survive.
Wombats have also been hit hard. They don't cope well with heat or stress and panic at the smell of smoke. The small, stubby-legged marsupials can't run very fast or far and are largely at the mercy of the flames.
"It's just horrendous," said Graeme Jackson, a NSW resident who has experience raising orphaned wombats. "A wombat can run 30 kilometers (per hour/18.6 mph), he can run that fast (for) short distances, and then he burns."
Other species don't die from the flames or smoke, but instead from the fire's aftermath. Smaller mammals and reptiles can escape the blazes by burrowing underground or hiding in rocks, but afterward, there is no food or shelter left, only certain predators that are drawn to fire because they know it brings easy prey.
"The big issue is that feral cats and red foxes hone in on fire front. They come in and pick off animals. It's an open hunting area," said Dickman, from the University of Sydney.
Koalas and kangaroos are spread out across the country, so they're not in danger of going extinct due to the blazes. But other animals that live in niche environments and have smaller populations may have been wiped out entirely; these include the eastern bristlebird, the mountain pygmy possum and the corroboree frog.
For these species, "if its habitat burns, it's a goner," Dickman said.
Extinction doesn't happen all at once. Each species on Earth has an average of 220 populations, so a healthy species could recover if only a handful of populations die out. But "if you whittle away population after population, then eventually you'll be left with half a dozen, then three, two, then maybe even one population," Dickman said. "Then all it takes is one event, and it's gone — a fire, drought, whatever."
Photos: Deaths, damage mount in Australian fires
Warning: Some photos contain graphic content.