Why cats prefer silver vine to catnip and other May highlights

It’s a regrettable reality that there is never enough time to cover all the interesting scientific stories we come across. So every month, we highlight a handful of the best stories that nearly slipped through the cracks. May's list includes the discovery of a possible prehistoric mining site in the Pyrenees; a new species of tiny blue octopus; why cats seem to prefer silver vine to catnip; and why political polarization might behave like a phase transition, among other noteworthy stories.