Gelada baboons, Simiya and Jilo, broke with tradition when they took time out from grazing for a little rest and relaxation.
Keepers spotted the boys grooming in their indoor den – and made a dash for the camera to record their behaviour!
Lower Primates Section Leader, Nicola Wright said: “Geladas spend the least time grooming each other than any other primate, because they have to graze and pick a lot of blades of grass in a day they are the only primate whose primary source of food is grass, so they don’t have a lot of time to spare.
“So when we spotted these two boys through the window of their indoor den, they looked so chilled that we had to capture it on camera!”