Not many people see me as an animal lover, but I really do value our non-human companions. That's why I think most pets should never have been born.

Take an example from my family's recent history...

We had two rats, which weren't getting a lot of attention. They weren't mistreated, they were well enough fed and watered, and their cages were a good size (more than half a square metre per rat), but they were left in there most days, and rats can really look bored. Every now and then the kids would ask for another rat or some other creature, and I would say no - if they could ignore two, they could ignore three or four.

Then my wife visited a pet shop, whose proprietor spun her a tale about these cute ickle baby rats which had been abandoned by a cruel buyer (everybody say "aaah"). We were a little way from home, visiting my mother, who happens not to like rats AT ALL, so subterfuge was called for. Despite my mother's "No" and my "No", off went wife and kids to bring back a pair of dark little cuties, which had to be held in the car because my mother wouldn't let them into the house.

These two little brothers soon turned out to be brother and sister - rapidly pregnant sister - and in what seemed like the blink of an eye there were fourteen blind, pink things squirming in the nest, and the one who hadn't given birth was less than welcome. Well, how would you like to have fourteen babies at three or four months old?

Action stations! This was a serious responsibility. We procured an extra cage, watched the tiny creatures like hawks (not a good analogy, really) and booked a visit from knowledgeable Aunty Beep to confirm our sexing and separation policy after as few weeks as possible.

We got it right and ended up with fourteen endearing teenage rodents in two cages, all with the potential of trying to better their parents' score. We could have had a population of 34000 by the end of the year if we'd left them to it and sacrificed our lives to supplying boring dried food and massive quantities of toast and jam.

But we didn't. Someone came up with the brilliant idea of selling or giving the little ones to a pet shop, and two single-sex batches ended up at animal emporia on opposite sides of town - you can't be too careful with rat pheremones. Unfortunately, the less brilliant idea of holding on to two of each sex also occurred to someone and was adopted despite my vigorous opposition.

So we had eight rats, and they weren't getting enough attention...

One or two rats can be great fun. They will interact peaceably with humans, run around the front room exhibiting their undoubted intelligence and their remarkably human-like interest in looking through holes and turning things over in their hands to investigate (I'm sure that's what frightens people at least as much as the scurrying speed and the threat of disease). They very rarely bite through electric cables and explode their heads (it has happened, but I've been off on too many tangents already).

... and they were massively inbred (in common with most pet shop rats) and susceptible to tumours which are mostly non-malignant (unless of course they happen to be located where they obstruct the useful functions of eating and breathing). And after two or three years they are now going out not with a bang but with a whimper.

We have experience with various other creatures...

Budgerigars are gregarious birds which fly great distances in enormous flocks. You knew that? So why do we mostly buy just the one and never even let them out of the cage? Our birds have always had the "run" of the front room, and my younger son in particular has "tamed" the latest one so that it will nestle in his jacket. In the wild, they nest in holes in trees.

When the bird scuttles round the floor investigating the rabbit, or runs up and down the draining board to take a shower from the dripping kitchen tap, it's funny and we are stimulating our pets' underused brains. But what kind of life are we giving them?

What kind of life can tropical fish have in a small tank? Not bad, you may think - they're safe and stupid - until you realise they spend much of their time banging their noses on the glass as they try to commune with the other fish in the outside tank - their own reflections.

Hamsters are interesting. They are solitary by instinct - even mating is a haphazard and frequently dangerous practice - but they would rarely reach one year old in the wild. So if you give them enough space - our best one decided that Rotastak and an enormous sand tray was kid's stuff and took to exploring the house - you may be giving their instincts a good run and they might live to be three.

So, what kind of life do we give these creatures? They may last longer than they ever would in the wild, but do they live anything you could call their own life?

We exploit a dog's pack instincts but try to install ourselves as the head of the pack (not always successfully) and stop them associating with other dogs (we decide what makes a pack).

Cats are probably the most successful at keeping to their way of doing things, but then we keep so many of them that they threaten to wipe out large parts of the wildlife we claim to value (it's not a long way from a chaffinch in the garden to a finch in a cage which doesn't even have to open its wings to hop between the perches).

As I said, I like animals, but are we honest with ourselves about why we keep them, and what we do to them?