The creature that sleeps through fires

Bushfires are an ever-present threat in Australia, but short-beaked echidnas have found a surprising way to survive them

In the tinder-dry bush of Australia, wildfire can tear through vegetation at terrifying speeds, incinerating almost everything in its path and leaving little more than blackened desert in its wake.

Most animals have a natural, ingrained fear of fire that compels them to flee the flames. But one strange creature has a rather surprising tactic for dealing with blazes. It does nothing.

Short-beaked echidnas - odd little hedgehog-like critters that lay eggs instead of live young - can enter an inactive state known as torpor, which is used by many animals to help them conserve energy.

When in torpor, echidnas reduce their metabolic rate and lower their body temperature.

This, according to research published in April 2016, gives them an uncanny knack for surviving bushfires. It might also have helped their distant ancestors survive a mass extinction.

In 2013 a catastrophic fire swept across Warrumbungle National Park in eastern Australia. Julia Nowack, then based at the University of New England in New South Wales, Australia, studied the aftermath.

She and her colleagues noticed that short-beaked echidnas were among the few survivors. Even in areas that had been reduced to ash, the spiny mammals were roaming around, apparently unperturbed.

Echidnas often nest underground in burrows or inside fallen logs, which protects them from the heat of the flames.

But fires often have a longer-term impact. Echidnas mostly eat ants, and any such six-legged snacks either flee or get roasted by the blaze.

This led Nowack and her colleague Fritz Geiser to wonder if the echidnas were using torpor to help them survive the fires.

"Foraging activity during a fire can lead to animals being trapped in burning areas or being hit by falling trees," says Nowack. "So staying inactive during a fire is likely to be the safer option."

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