Cats are scientifically, objectively, monumentally terrible for the planet. In the US alone, free-ranging domestic cats kill up to 3.7 billion birds and 20.7 billion mammals a year, to say nothing of reptiles and amphibians. They are a scourge of the highest order.Now felines are poised to exacerbate the ecological crisis unfolding in Australia as an unprecedented fire season rips across the continent. Scientists have previously shown that feral cats hunt surviving animals across recently burned lands in Australia, exploiting many of the victims’ injured or weakened state. One study found that a feral cat journeyed 19 miles to a burn scar. Roaming cats might stay away for up to 50 days, massacring helpless locals on a now barren landscape. (They’re likely using a combination of sight and smell to pinpoint bushfires by their smoke.)In another study, researchers attached collar cameras to 13 feral cats and recorded 101 hunting events in an Australian savanna, of which 32 were successful. All told, the kill rate was equivalent to 7.2 victims per cat every 24 hours, and the hunters didn’t even eat their kills a quarter of the time—they’re what are known as surplus killers. The cats were particularly successful when hunting in open areas roughly analogous to a fire-torched landscape, with successful kills 70 percent of the time. Yet another study found feral cats are highly attracted to areas that burned recently and tend to avoid ones three months or older, perhaps because vegetation has begun to grow back by that time, or they’ve simply obliterated the prey species there.
Australia is lousy with cats, as the invasive felines have established themselves in all but .2 percent of the country, according to one estimate. At their most plentiful, 100 cats may pack into a square kilometer. Because no cat is native to Australia, native species aren’t adapted to avoid and escape them. Accordingly, the Australian government has launched a large-scale feline eradication effort to try to save the natives from destruction.
At the same time, the continent has become a dramatic stage for the ravages of climate change. A hotter world means drier vegetation and bigger fires , and this season’s fires are behaving in astonishing ways: Instead of a mild bushfire burning here and there, now the conflagrations are leveling entire ecosystems. Species used to be able to escape to, say, a neighboring rainforest, but now Australia is so dry that even rainforests burn straight through. Millions upon millions of acres have burned in the past few months, and the fire season is nowhere near done.
The severity of this year’s fires is unparalleled, says conservation biologist Sarah Legge, who studies the impacts of feral cats after bushfires. “In terms of the potential for recovery, that's something that worries us a lot.”Some areas in Australia that typically burn once every 50 to 100 years have burned three or four times in the last two decades. “They haven't had a long enough time to recover before they get smashed by another fire,” says Australian National University ecologist David Lindenmayer. “And that means that there's a very high inherent risk of the system collapsing into a different kind of environment.”
With the massive fires of the past few months, scientists won’t know the full extent of the damage until they can get in there and do surveys. What they do know is that animals face several stressors after any bushfire. Their prey may have perished or fled, and herbivores have had their vegetation wiped out. Not helping matters is the fact that Australia is withering under a brutal drought, so wildlife is already suffering a lack of water.