Great tits avoid bad food after seeing grossed-out friends

BIOSPHOTO/Alamy Stock Photo

Great tits that exhibit disgust when they eat a horrible meal may inadvertently be driving their prey to evolve.

Many prey animals have evolved deterrents so that predators will be reluctant to eat them: they may have an unpalatable taste or even be poisonous. They often signal this with bright and contrasting colours, like the yellow and black stripes of a wasp.

But it’s not clear how these “aposematic” signals evolved. “Predators need to first learn the signal before they avoid it, but until they do these prey are very easy to detect and kill,” says