Viruses love bats. The flying nocturnal mammals make outstanding hosts because — just like people — they live in large, dense groups, their air travel spreads germs between populations and their longevity enables a virus to persist for years in an individual animal.

The big difference is that bats’ remarkable immune system tames and tolerates many viruses that cause havoc when they spread to humans, including the coronavirus responsible for Covid-19.

“We should look at what bats are doing to control the virus and emulate that in some way,” says Bernard Crespi, professor of evolutionary biology at Simon Fraser University in Canada, one of a growing group of scientists finding clues to the pandemic through bat immunology.