Perhaps it is the black, loose-fitting robes that he and his equally-bald band-mates currently favour on stage. Or maybe it is his soothing, ever-more-measured speaking voice. Whatever the reason, there is something increasingly monkish about Peter Gabriel. Indeed, as he thoughtfully strokes his grey goatee, I half-expect him to begin quoting the Dalai Lama. Instead, he tells me that his calm exterior is in his genes: "My dad's way of dealing with life is quite reasoned and philosophical, so I guess I've got a fair bit of that."
Gabriel and I have met to talk about his upcoming UK tour. In reality we shoot the breeze on Kate Bush's forthcoming album ("I haven't heard it either, but I'm sure it will be a treat."), gifted apes and plenty more. His 29-year-old daughter, Anna, is nearby, too, the better to field questions about Growing Up, on Tour, the fly-on-the-wall documentary she has made about her father's last live outing.
Gabriel is one of those rock stars famous for his humanitarian concerns. They are easily derided, these millionaires with hearts and combative minds, and easier still to beat with the "egotist" stick. Still, if today's political situation required someone to write a powerful anti-apartheid song, it's hard to imagine anyone, other, perhaps, than Radiohead, stepping forward. And even if they did, the resultant tune would be unlikely to be as strong as "Biko", the 1980, Gabriel-penned, tribute to the South African activist, Steve Biko.
Since that time, Gabriel has been a major supporter of Amnesty International and has supported world music via signings to his Real World label. Since 1992, he has also worked closely with Witness (see www.witness.org), an organisation distributing free video cameras to facilitate eyewitness recordings of human rights abuse. "Obviously, we're dealing with an incredibly widespread series of problems there," Gabriel says, " and so far we've only been able to get 200 or so cameras into 50 countries. The key point is that video evidence tends to gets results, whereas text-based reports do not."
If the inherent worth of work done by Witness is beyond dispute, other Gabriel projects have been received more sceptically. "During the making of his 12th solo album, Gabriel "jammed" with some musically-inclined bonobo apes", wrote one critic, reviewing the album Up. "You can hear Brian Eno gnashing his teeth because he didn't think of that first."
The inference was that Gabriel's experiments with the primates of Georgia State University's Language Research Lab were a mere dalliance, a rich man's conceit, and a further measure of the kind of eccentricity which once led Gabriel to dress as an alien with an inflatable penis. Lord knows what the critic would make of ApeNet (www.apenet.org), a Gabriel-endorsed project to help primates get online. "A lot of people make fun of that stuff", Gabriel says, "but I'm completely at ease with it. I'm also at ease with the idea that, 100 years from now, we're going to realise how slow we were to see the intelligence of species that surround us."
Gabriel says he was cynical about purported levels of primate intelligence until he travelled to Georgia to see some of the work Dr Sue Savage-Rumbaugh was doing. "One of the gorillas was upset after 9/11", he says, by way of example. "She sensed the people around her were disturbed, but she didn't know why. They showed her the relevant TV news footage, and she then signed: 'People in aeroplane/ crash into building/ people die/ I'm sorry.' That's the level of comprehension we're dealing with here."
Gabriel retrieves his Apple PowerBook from his bag and shows me footage of his keyboard jam session with a female bonobo ape. Panbanisha is requested to play with one finger, and to use only white notes. She understands, and responds to both these provisos. Gabriel, meanwhile, is in another room, playing some string synthesiser in A minor. Panbanisha is a model of concentration as she picks out a basic, but unmistakably deliberate, melody in response to Gabriel's chords. At one point, her sizable digit depresses two adjacent keys accidentally, and she responds to the resultant discord with an all-too-human grimace. But then she re-asserts herself, and begins improvising a new melody, with an inventive use of octaves.
"Sometimes we weren't connecting and other times I could really feel Panbanisha's energy and focus," he says. "Then her brother, Kanzi, came in and I had a little jam with him, too."
Gabriel's Growing Up tour was one of the most acclaimed of 2003. And now comes - wait for it - the Still Growing Up tour which retains director Robert Lepage's spectacular coups de théâtre (like the giant "Zorb" ball which Gabriel rolls around in, and the "upside-down stage"), but the singer will also be shaking up the set list to incorporate more intimate numbers.
Within and outside the show, Gabriel has sought to strengthen his family ties. His other daughter, Melanie, sings back-up vocals, and his second wife, Meabh, and three-year-old son, Isaac, were also non-performing fixtures on the last tour.
"It comes down to a different set of priorities", he says. "I think I gave Anna and Mel more time than most rock-musician parents, but in your twenties you've got your own ego and your own life to carve out. At this point, I've done most of what I need to do in the world. I'm 54 now and want to stay fit enough to take Isaac snowboarding, or to kick a football with him when he's a teenager. Basically, I'm relying on major advances in medical science!"
Joking aside, Gabriel may not need to rely on such advances if he takes after his father. At 92, Ralph Gabriel is still practising yoga, and one of the most touching scenes in Anna Gabriel's documentary sees her make use of camcorder footage shot by her paternal grandmother. The clip shows Ralph and Peter Gabriel doing yoga together, an experience which inspired the part of "Father, Son" which runs: "Locked as one/ In this empty room/ Spine against spine/ Yours against mine."
"I appreciated that intimacy tremendously", says Gabriel. "And it was part of the motivation for doing it, though perhaps not consciously. More than that, I wanted to spend some time with Dad because he's obviously getting on. I'd been introduced to a yoga teacher who did two-person stuff where you use the other person's body as a fulcrum to stretch you, and I thought, 'Why not?'
"There's this idea of the body being a big tape recorder of emotional moments, and, at one point, I completely lost it, and started sobbing uncontrollably. My father grabbed me like I was still his little boy, and we hadn't had that since I was a child. The teacher was in tears as well. It was powerful stuff."
I wonder if he mourns the passing of the years. "Sometimes I laugh when I see my younger self, sometimes I cringe, and sometimes I'm touched", he says. "But I haven't mourned the passing of the years since I stopped fighting them. In my forties I was still dyeing my hair and trying to be something other than what I was. Now I'm just happy being myself, for better or worse."
Peter Gabriel's 'Still Growing Up' tour plays the UK from 1 to 8 JuneReuse content