Michael McCarthy: You needn't travel far to find a monster

Nature Notebook: The pike's emergence somehow justified another, age-old fear, that hidden depths must hold horrors

I saw a monster at the weekend. It came from the depths. It filled me with awe. It almost filled me with dread. There was certainly a bit of dread in there somewhere.

It was a pike. It weighed 22lbs, and I watched a man catch it from a river in Hampshire, and when it came out, and it was briefly on the bank – he put it right back – I couldn't take my eyes off it. It was the size of a gatepost, a fat gatepost with killer teeth, and it was beautiful beyond words and terrifying at the same time.

The monster-dread clearly loiters deep within our genes, from the thousands of human generations when we might have been prey as much as predators. A millennium after the last British bear was killed off, we don't have many monsters in southern England, a neatly-tended landscape typified by the cottage garden; but the pike will do.

I spent some time trying to work out why the sight of it was quite so engrossing, and first, I realised, was that such creatures are rarely seen, let alone in such intimate proximity. It's a lot harder to be a fish-watcher than a birdwatcher. Second, it was the fact that it had come from beneath the surface, the shiny pewter surface of a winter river, and its emergence somehow justified another, age-old fear, that hidden depths must hold horrors. Third was its sheer beauty, this lovely lozenge of emerald green and yellow, but fourthly and most tellingly was its unmistakable identity as a killer, its whole streamlined shape designed for slaughter.

It might not be able to kill us, but it's not the size your imagination fixes on, it's the killing ability, and anyway, as Ted Hughes said in his famous poem, capturing the point exactly, pike are "a hundred feet long in their world". Hughes's poem is one of the best of his intense evocations of wild creatures, the muscular language perfectly matching the brooding savagery he is describing; only the passionate fisherman that he was could have produced it.

Odes to the pike

There is another poem about pike which is now much less well-known: it was written in 1919 by Edmund Blunden, one of the First World War poets who survived, like Siegfried Sassoon and Robert Graves.

Blunden's flowery diction is a world away from Hughes's tough talk, but the poem works just as well in conveying the essence of our aquatic assassin. Comparing and contrasting them would make a good A-level English question, but forget that, why not have a go yourself? They're both on the internet. If you love the natural world and you love poetry, you'll come away enriched.