Greetings are found across the animal kingdom. Dogs sniff each other’s rears, African elephants swing their trunks, and songbirds peck at one another’s feathers. Orcas face off in rows before rushing into a sort of whale mosh pit, in which they slap tails, squeak, and whistle. Greeting behaviors are universal enough that they are thought to be ancient, emerging before primate groups evolved. When a spectral bat wraps its wings around another bat in what looks like a hug, it seems to be communicating something that we’re familiar with.