Using cutting-edge optogenetic techniques, Dulac was able to activate the galanin cells in virgin males on the verge of killing infants. Their transformation was instantaneous. The males started building nests, and carefully placing pups in them, which they then groomed and huddled protectively. ‘The male mice were “maternal” – they took care of pups in exactly the same way a mom would do, the only difference being that they couldn’t lactate.
