From Caroline Peters, Winnersh, Berkshire, UK
You report that hyenas make a face when they want to play-fight (2 October, p 23). Cats also make play faces. Our 11-year-old arches her whiskers forward and opens her mouth slightly when playing. Her expression when hunting or fighting is very different – the play face can’t be mistaken. I have had numerous cats over the years and they all had a distinctive play face.
