Cat and mouse may never be the same. Japanese scientists say they‘ve used genetic engineering to create mice that show no fear of felines, a development that may shed new light on mammal behavior and the nature of fear itself.

“Mice are naturally terrified of cats, and usually panic or flee at the smell of one. But mice with certain nasal cells removed through genetic engineering didn‘t display any fear,” said research team leader Ko Kobayakawa.

Kobayakawa said his findings, published in the science magazine Nature last month, should help researchers shed further light on how the brain processes information about the outside world.

“People have thought mice are fearful of cats because cats prey on them, but that‘s not the case,” Kim said.