With terrifyingly sharp teeth arranged around a circular mouth, lampreys look about as primitive a vertebrate as you could imagine. But a new study finds that the animals have a surprising similarity to people: Lampreys have the nerve cells responsible for the “fight or flight” response. The finding challenges the idea that this part of the nervous system emerged later in evolutionary history, and it puts lampreys closer to complex vertebrates — like humans.
“The conclusions are textbook-changing level,” says Daniel Meulemans Medeiros, an evolutionary biologist at the University of Colorado Boulder who was not involved with the new study but has worked with the research group before.