“Can you hear that?” says James Higham.
I can. It’s a loud screeching noise in the background of our phone call.
“That’s a female rhesus freaking out,” he says.
Rhesus macaques have featured heavily in lab experiments, but this particular loud female is part of a wild group, living in Puerto Rico. Higham, an anthropologist from New York University, is studying them. He is interested in their faces, which vary from a dull pink to a vivid red. Specifically, he wants to know if the females judge the males on the intensity of that colour.
“I’m stood about 5 metres away from a sub-adult male and he’s with a 3-year-old female, ...