Spring in Canada can be an unconvincing season. In Montreal, where I used to live, the weather will suddenly turn warm, and the sun can seem like a youthful idiot shouting THERE’S HOPE, THERE’S HOPE to an audience of corpses. On a day like that, I drove to a place that changed my life.

I was approaching forty. I was madly in love. I was daily aware of the inadequacy of words to describe the joy and ache I felt, and at the same time I had no need for words. I went to a lousy therapist and told her how good I felt and she said she had heard the same from a number of men recently: adultery had done them good. I was in the middle of a divorce, and had done some truly shitty things to people I loved. My son was born in the midst of my failure to stay married. Regret had left bruises behind my eyes.

Having read so much about chimpanzees I had to adjust to them as animals when I met them, as flesh and blood rather than abstractions. Study after study presents them as embodiments of data: they are sensitive communicators; they remember sequences of numbers; they get depressed in middle age. The data are often wonderful and telling, but they somehow collect in a corner – that place we look when we are searching for random facts and cute coincidences, those moments when the ‘natural’ world might amusingly reflect our own. The further we get from having to find our own food, the less awareness we have of our nature. Understanding these individuals at the sanctuary as animals meant adjusting to myself as an animal. I was not finding an ape within. I was realizing that the whole of me is an ape, that our genes, our biology, our behaviour in groups are not just coincidentally related to other apes but inescapable facts that I arise and go to sleep to. That I dream with.

We all embody a range of contradictions. Chimpanzees and humans hate to see injuries, and cause them all the time. Chimps and humans choose their factions, betray their friends and use enemies to consolidate friendships. While I hate the violence that humans have inflicted on chimps, I’ve seen chilling and deplorable fights between chimps themselves – capricious acts of bullying and murder which show that they can have as much disdain for life and kin as we can.

Lana, the joyful, curious chimpanzee who learned how to use the computer to talk to Tim, ended up being kept in the lab at Yerkes and became part of the breeding programme. I recently met a woman who worked with her on that original language study. She had returned to Yerkes and met Lana again, forty years later. She said that Lana clearly remembered her. Lana had had several kids at Yerkes, all of them taken away from her for various studies. The woman said that Lana’s eyes were distant, and sad.