This second phase can drive the attachment in mums, dads, other more distantly related kin and even foster parents. It has been observed experimentally in virgin female rats, which are normally extremely hostile towards pups, ignoring or even devouring any they happen upon. But if a virgin is repeatedly exposed to pups, especially if she has a mother to learn from, this inexperienced au pair from hell stops killing and starts nurturing until eventually she’s as attentive as a birth mother.
