The whippet snapper: Man's best friend in pictures

The way we look at dogs, says the photographer Jo Longhurst, reveals far more about us than it does about the dog. They portray the quality and power of their owner: a stocky Staffordshire bull terrier represents toughness and a snooty Afghan hound stands for refined and expensive elegance. "We've bred them to a certain shape, to conform to our desires. In Victorian art a dog would be a symbol of fidelity, of loyalty. There's the classic image of an owner in front of his country estate with hunting dogs. Rather than projecting ourselves on to them can we approach them for the beasts that they are?" she asks.

In a series of photographs titled The Refusal, Longhurst explores the intense relationship we have with our dogs, from the way we primp and preen them before a show judge to our ideas about their psyche – she photographs her dogs dreaming, teeth bared as they growl at an imaginary beast. All the dogs she photographs are whippets. "I was drawn to whippets because they have been in all aspects of society. They are an old English breed and have a home with the working classes because they were used for poaching and the aristocracy kept them for hunting. Now they're a domestic pet for the middle class.

"For an artist they have a wonderful palette, with a variety of colours. There are reds and fawns; lemons, creams and golds; blues and blacks: plain, brindled or parti-coloured coats, in any combination," she says.

In a series of individual portraits of champion whippets, 12 Dogs, 12 Bitches, she photographs the dogs in profile, the angle from which they are judged at a dog show. They're clinical images, taken with a cold eye, on a white background. The dogs are the ideal, presented solely for their aesthetic appeal. They have been trained to stand in a specific position; the controlling hand of their breeder keeps them in place.

The dogs have comically grand show names: Nevedith Zedfa Zappa, Champion Walkabout War Waggon from Stormalong. "They are fabulous dogs but it's very different to the way I understand a relationship with dogs, this aspirational idea of the perfect show dog," she says.

She was particularly drawn to one bitch, Lily. Her full name is Darquell Silver Dollar of Shoalingham – and she is beautiful, an almost transparent white, with patches of fawn, her muscles outlined beneath a fine layer of fur. She has defiantly stepped one foot out of line. "I like the fact that there was this purposeful step, it's a space of positive rebellion against the expectation to stand in the perfect pose. I liked her attitude," says Longhurst.

When she began the project back in 2001, Longhurst took her own whippet, Vincent, to shows around the country, hoping it would be a good way to meet dog breeders who would let her photograph their dogs. Unfortunately, Vincent has a roached back and is very thin, even for a whippet. No one would speak to them. "If I'd been there with a beautiful whippet then I think people would have been more friendly. The class structure now is that if you breed good whippets, you're in," she says.

She did eventually find breeders willing to participate. Most breeders adore their dogs but there is an insidious side to dog breeding in so far as we impose our own values, of beauty and form, on to the animals. Whippets used to be bred for their good eyesight and speed; now the criteria are largely cosmetic.

In her next series of photographs titled I Know What You're Thinking, Longhurst presents the dogs in a way that she feels is more familiar to her own relationship with dogs. In these huge portraits, the dogs are photographed close up and face on: their liquid brown eyes look straight into yours, pleading to be loved. It's tough to feel nothing in front of these photographs, and they will melt the heart of any dog lover.

There is a human quality to their features: eyes, cheekbones and nose. This sense of familiarity makes it seem that, as a species, we're not so far apart. "The fact that dogs can't talk is fantastic. They are sufficiently familiar to us for us to have an understanding with them. We can have an intimacy with them, a relationship. They share our world and habitat. We spend more time with them than with most people. I spend a lot of time on my own, which is why I got a dog in the first place. I wanted companions that I could deal with. They're fantastic company," says Longhurst.

Longhurst delves into the dog psyche. For the series It's All In My Mind, she photographs Vincent as he dreams, his brindle stripes contrasting beautifully with the fur rug he is sleeping on. The viewer can only imagine the dog dreams going on inside Vincent's head: fields full of giant rabbits and heroic fights with killer rats. "A lot of critical theory discusses the animal as the biological machine. They say there's no proof that a dog dreams, yet I have seen dogs barking in their sleep and acting like they're chasing something. Freud thought that dreams were the key to our psyche. When dogs are asleep and dreaming, we have an empathy with them as something living, with feelings and emotions," she says.

One thing Longhurst loves about dogs is their indifference to image. In The Refusal (Part III), she photographed the dogs in front of a mirror. The reflected image creates a symmetry where one dog looks like two as they perform like dancers, necks twisting elegantly to one side and backs arching in perfect unison. In all the photographs, the dogs avoid looking directly into the mirror. "We're so obsessed with image and they don't care. By not being interested in looking at themselves, they have a freedom that we don't have," she says.

When the photographs were first exhibited, Longhurst invited all the dogs to the opening, which was held in Southwark Park, south London. Vincent strolled around with a camera fixed to his head and the footage was shown live on a television screen in a dog cage inside the gallery. There was much sniffing of noses and bums. For the most part, the dogs didn't respond to the images, although when they were shown at a photography festival in Arles, Longhurst arrived one morning to find the wall by her dog portraits covered in large muddy paw prints.

"One of the press had been at the festival early in the morning with his dog. When they turned a corner they were suddenly confronted with these enormous photographs of dogs. The dog went berserk, running at the photographs, barking like mad and jumping up at them," she says. "I was flattered."

An exhibition of photographs from 'The Refusal' will be shown at the Royal College of Art, London SW7 (020-7590 4444) from 30 May to 7 June; 'The Refusal' by Jo Longhurst is published by Steidl, priced £15