Nature Studies by Michael McCarthy: When one beast must die – to let another live

One of the attributes of young schoolboys – or at least it was, centuries ago when I was one – is the impulse to gather round, fascinated and excited, when a fight erupts in the playground. I mean a serious fight, a grudge match between two boys going at it hammer and tongs. Shouting breaks out. Sides are taken. Emotions run wild, until the teacher arrives to break it up. Is it a purely male attribute, this animated reaction, or is it a universally human one? I've no idea. Although you may disapprove of it, it most undoubtedly exists. It's in the genes.

I think it was some of this instinct which kicked in on Wednesday night when the much-lauded BBC series Frozen Planet showed, among astounding scenes of weasels hunting voles under the snow, and baby polar bears being born, and the brinicle, the icicle of death in the sea – if you missed that one, you'll just have to look it up – the single most remarkable piece of wildlife footage I have ever witnessed. It was a fight between a bison and a wolf.

It took place in the snowy landscape of the Wood Buffalo National Park in northern Canada, and although you couldn't really call it a grudge match – there was obviously nothing personal, if you see what I mean – it was most definitely serious. It was a fight to the death, where one participant had to die so the other could live. A zero-sum game, as the cliché used to have it.

We have grown used to predator-prey dramas in our natural history documentaries: we have all seen the lions chase the wildebeest, and bring it down and kill it, or owls catch their mice with a swoop and a flick of the talons, and, in the nature of things, these are over quickly; but this was different. It was a lone wolf, and a lone bison, and most unusually, they were very equally matched, so although at first you thought "well, the sharp-fanged killer is bound to win, isn't it?", the next moment the bison tossed the wolf through the air like a rag doll, and then trampled it with its half-tonne weight, and you thought, "wow, how can it survive that?".

It was unbelievably fascinating. It was unbelievably exciting. The inner schoolboy in me was shouting, and it was impossible not to take sides – and I wondered later if it said anything about your personality if you sided with the wolf, or sided with the bison – although, I found my own loyalties shifting, first supporting the bison, which was only trying to avoid being eaten, and then sympathising with the wolf, which was only trying to avoid starvation.

And it went on, this epic battle. It went on, and on, and on, and Jeff Turner, the wildlife cameraman who had spent 15 years waiting to film something like this, and who was barely 50 yards away, said later that it continued for more than an hour, although, of course, the footage shown lasted only a few minutes. Yet you could tell what a long, drawn out affair it was, because gradually the coats of both combatants became red with blood, and their movements slowed as their strength ebbed away.

Finally, they stood in the snow, facing each other, completely exhausted; and they had both been so brave and tried so hard that suddenly you wanted to be the teacher in the playground, or the referee in the boxing match, and stride forward and say in effect, "All right, you've both done really well, you've shown a lot of pluck, but that's enough, so go inside and get those cuts sorted out."

But, of course, there are no intervening teachers, no referees, in the natural world, and the zero-sum game had to play itself out, and it was the bison in the end which succumbed, with my inner schoolboy silent now, shouting no longer.

The battle to save the Arctic's environmental future is gathering pace

Frozen Planet, narrated in perfect tone and cadence by David Attenborough, has undoubtedly moved many people, and made them aware of how rich, beautiful and untouched are the ecosystems of the Arctic (and the Antarctic, too, of course). But it may have done more than that: it may have made them sympathetic to the fight to protect the Arctic's environmental future, which is about to begin.

Next year, a new oil rush will begin above the Arctic Circle, led by Shell, drilling in the Beaufort and Chukchi seas north of Alaska, and followed by ExxonMobil, which will be drilling with Russian partners in the Arctic Ocean north of Siberia; but next year, too, Greenpeace will launch a major campaign to internationalise the High Arctic and make it a "global commons", owned by no one and free from industrial development. Greenpeace has been joining in the enthusiastic tweeting which accompanies every Frozen Planet episode, inviting people to join its Arctic Campaign: it says the response has been "substantial."

m.mccarthy@independent.co.uk