New Zealand's highly intelligent parrot, the playful kea bird, has a contagious "play call," like human laughter, that makes other kea birds want to play more. A new study in the journal Current ...

Human laughter is such an intrinsic part of our lives that we don’t tend to give it much thought. But we are one of only a handful of animals that do it, along with apes, dogs, and, quite bizarrely, ...