PREVIEW

Scientists are newly worried about the potential spread of viruses like Covid-19 after viewing footage of rats hunting and devouring bats.

Bats are known to carry a wide range of viruses – including relatives of the coronavirus that caused the Covid-19 pandemic. But as bats rarely come into contact with people, scientists have long wondered how these viruses might pass from bats to humans.

Now, a new study from Germany has revealed an unexpected potential link. Researchers studying bat communication accidentally filmed rats attacking bats – even snatching some out of mid-air.

Dr Mirjam Knörnschild, a head of evolutionary diversity dynamics at the Museum of Natural History in Berlin was horrified by what she saw, telling NPR it “happened again. And again.”

The team, using an infrared camera in a cave in northern Germany, recorded brown rats ambushing roosting bats in total darkness.
“Bats can echolocate, so they should have been able to detect the rats,” said Dr Knörnschild. “But how the rats managed to spot the bats is still a mystery.”

The researchers believe the rats likely came from a nearby open-air theatre in the town of Bad Segeberg, a tourist hotspot where discarded food attracts rodents.

To find out whether the behaviour was unique to that site, the team surveyed another cave in Lüneburg, near Hamburg – and found similar attacks, along with partially eaten bat carcasses.

Urbanisation, the study warns, is pushing rats deeper into natural habitats as they seek food and shelter, bringing them into closer contact with wildlife.

The findings have also caught the attention of disease experts. Professor Raina Plowright, an infectious disease ecologist at Cornell University in the United States, told NPR the results raise questions about whether rats could act as a “bridging host” for bat-borne viruses.

“Rats are perfectly adapted to human environments – they live everywhere we do,” she said. “As we degrade natural habitats, we bring rats with us, and potentially a bridging host that could expose us to the next pandemic pathogen.”

The fears are especially troubling as rats are a known conveyor of disease to humans - most notably in the case of the medieval plague, The Black Death.

Dr Knörnschild’s team is now working with Germany’s Federal Environment Agency, the Umweltbundesamt, to explore humane ways to manage rat populations near bat colonies - and potentially prevent a new pandemic.