John Mullan on the uses to which animals are put in Yann Martel's Life of Pi
Life of Pi by Yann Martel
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Literary critics, as well as booksellers, should recognise that Yann Martel touched nerves with his story of a teenager cast adrift on the Pacific in a lifeboat with a zebra, a hyena, an orang-utan and a Bengal tiger for company: animals have always played important roles in fiction. The majority of illustrated story-books for pre-literate children have animals as their characters. Much of the most powerful fiction for older children - from Black Beauty to Narnia to Harry Potter - makes animals participate in human adventures. And "adult" fables, from Aesop to Gulliver's Travels, have always used animals to project human inclinations outwards in order to make stories.

Narratively speaking, animals commonly simplify human characteristics and have therefore a primal role in the business of story-making. You might read Life of Pi in this light, as a fable. When Pi reaches land after 227 days at sea, he describes the tiger with whom (or with which?) he has shared his boat as "companion of my torment, awful, fierce thing that kept me alive". A story so remote from likelihood must be "about" something, and here you are tempted to take the dangerous beast in the boat as the "animal" aspect of his nature that keeps the human alive. Yet far from being told like an allegory, the novel's central episodes are narrated, by Pi himself, with circumstantial precision. The situation is extraordinary, yet carefully explained. In the novel's first section we see Pi, whose father runs a zoo in India, acquiring his knowledge of animals. The animals are on the ship to Canada with him because the zoo has closed.

There was wide agreement that Life of Pi was an example of "magic realism". Yet the novel does so much to detail and explain the behaviour of the animals on the boat that "magic" seems a misnomer. Describing the conflict between the orang-utan and the hyena, Pi tells us that we are getting "the plain empirical truth", and this assurance rivets the whole account of human and animals. The book is full of its narrator's zoological expertise. Situations may be unlikely, without being magical. Martel's novel knows this. In one extraordinary episode, for instance, it arranges an "epic battle" between a mako shark and the tiger. Clearly this is the first such fight to be observed. "Of interest to zoologists I can report the following ...", says Pi, before giving us an empirically exact, bite by bite, narrative. Magic realism is typically a benign genre. The harsh material laws of life are suspended. Characters float above the ground; life does not end with death. In contrast, Martel's novel insists on harshness. If flying fish do (providentially?) land in the boat, Pi must describe his subsequent, inept efforts to kill one of them in gruesome, material detail.

We are thoroughly warned against anthropomorphism. The young Pi's father teaches him that an animal is "essentially and practically removed from us" by showing him a tiger (starved for three days in preparation) being given a live goat. The account is as fearful for us as for the child. Yet the narrator's understanding of the ways in which animals behave - which is the means to his survival - implies shared human-animal characteristics. When he approves the "savage courage" of the orang-utan's defence against the hyena it sounds like fellowship. It is a good joke that the tiger is called Richard Parker (a clerical error has given it the name of the hunter who originally captured it). For thus the reader is constantly tempted to mistake it for a human character. Yet the narrator's nuanced, utterly credible interpretation of the tiger's "emotions" (his word) lets us see that human and animal do have peculiar sympathies. Pi faces his ordeal with a prior knowledge of the "surprising living arrangements" to which animals sometimes come. Dogs treat humans as other dogs; dolphins "save" drowning men. Circus lions "don't care to know that their leader is a weakling human". His knowledge enables the "dealings" between him and Richard Parker. Pi learns that the tiger speaks "a simple, forcefully punctuated language that told me what his next move might be".

Life of Pi is not the first novel to look at human beings looking at animals. Nor is it the first to disavow sentiment in doing so. In Angus Wilson's The Old Men at the Zoo, the kindly humanist takes the fascination with animals of the zoo's visitors to be evidence of our better selves. Nonsense, replies his steely Malthusian colleague, people love animals "because they eat each other". In Martel's novel they eat each other with a minutely described voracity. Yet there is more than appetite. The carefully analysed processes of threat and bluff binding human and tiger are amusing as well as Darwinian because, through his animals, Martel invents a kind of primal psychology.

· John Mullan is professor of English at University College London. Join him and Yann Martel for a discussion on Wednesday October 3 at the Newsroom, 60 Farringdon Road, London EC1. Doors open at 6.30pm. Entry is £8 (includes a glass of wine). To reserve a place email or telephone 020 7886 9281