"We can stay all day." -- Tom Paxton

Nature My first feeling on entering The Twilight Zone, Chester Zoo's version of the bat house yesterday afternoon was melancholy. The enclosure was opened in 1998 by the late Douglas Adams, a committed supporter of animal conservation and whose book and radio series 'Last Chance To See' included the Roderigues Fruit Bat, one of the species thriving within this haven. I wondered how he'd feel now knowing that even though they're still on the brink, a colony survives and thrives in this area of Cheshire. I took a photograph of the plaque and then stepped towards the entrance.

There was another information sign nearby explaining that the bats therein would not get tangled in the visitor's hair and they certainly wouldn't bite you, oh and to walk slowly without making any sudden movements. It's then that I twigged that the house was designed so that human and bat would be sharing the same airspace. So my second feeling was one of anxiety, and the third was excitement - this was exactly the kind of experience I'd visited the zoo for.

During the remains of the day, cages and bars, pits and holes would stop man and animal from interacting too much, for good reasons in the majority of cases. In the jaguar house, a cat had sprung towards the crowd with paws and teeth and growl on full power and with such force that twenty people simultaneously jumped backwards possibly thanking the car firm who'd sponsored the enclosure for hiring the best glass manufactures money can buy. But sometimes you want to be David Attenborough, up close to the natural world, communing with the nature you'd only otherwise see on television.

You don't walk directly into shed holding the bats. First there's a display area collecting other animals and insects that could be found in their natural habitat. In a small tank close to the floor are Turkish Spiny Mice, a multitude of rodents holding and snuggling into one another. They're so called because the hairs on their back make them difficult for predators to swallow and cause an irritation in their stomach - which is hardly a consolation for the poor mouse digesting inside but their sacrifice protects the rest of the colony.

In another tank are the less cuddly Madagascan Giant Hissing Cockroaches, which are about the size of your finger and are exactly how you expect big exotic alien-looking entomological specimens to be. They make five different hissing sounds through the breathing holes in their abdomen which can help to frighten off predators but which are also used during territorial disputes between colonies and for courtship rituals. Incoherent noises being used to threaten and woo - not too far away from the average human really.

Then, walking through the kind of floppy plastic sheeting that used to be hung from the ceiling in a supermarket when the frozen food department was a walk-through freezer, I found a warehouse that has been turned into a manufactured habitat, filled with exotic plants. The space was about the size of a Tesco Metro except it was utterly dark apart from light leaking in from the roof. It was humid too and entirely unnerving. I heard a scream from the other side of the space and defined the silhouette of someone speedily walking for the doorway, whose light was reflected in an artificial pool ringed by a range of plants I'd only ever seen on science fiction sets.

I couldn't help but look up and already I could see them - the rafters were filled with bats. I stopped. I whooped. 'Oh my god' I said, 'That's so cool.' It's one of those moments when your ability to speak poetically, when all those long words you learnt in school simply fall away and you're left with a feeling of utter amazement, being faced with something you never thought you'd ever see in your lifetime. I mean they're hanging there, wings wrapped around them, a tiny head shifting left and right and up and down just as you'd imagine they would having seen the same thing in a hundred horror films.

The first thing I saw when I looked away for the first time was a small red light and a badge with the word 'Hello' scrolling across it in LEDS. I stepped closer and they were both worn by an attendant, someone who is no doubt there to make the bats feel less ill at ease with all this foot traffic walking through disturbing their sleeping and eating and everything else. She finished directing a family around the habitat and then approached and smiled, her badge already offering the expected greeting. I told her how amazing I thought it all was and she had a glint in her eye that indicated that she already knew that.

I mentioned the scream and she told me it happens quite often. I suggested it's because some people don't like being in proximity to something that they wouldn't otherwise encounter in their usual life and she agreed. I asked her if the bats ever do come in contact - I mentioned the sign and she explained that there are a lot of myths about the animals and they want to dispel them before people enter. Sometimes is works, I supposed.

She added that there are two types of bats there. The Rodrigues bats which are the larger, more visible species tending to keep to themselves and staying in the rafters. It's the other smaller kind, the Livingstons (or Sebas) which are friendlier diving in and out and the reason for the warning. I asked if they're still endangered. They are - there are only a couple of hundred of the Roderigues left in the world and about three thousand Livingstons (the website reveals that the zoo has fifty-eight of the former and around two hundred of the latter).

A school party arrived and I thanked her for, well, everything and continued along the path, remembering to walk slowly as instructed, still not able to keep my eyes off the bats. It's then I began to notice small drafts around by ears and hands, coming and going so quickly as to be hardly noticeable. There's a tunnel with lit information signs and its in here that I realised what was causing them - it's the Livingstons swooping in and out, their tiny shapes only vaguely perceptible in light of the perspex, scooting past and only narrowly avoiding me.

At first I jumped but after that I couldn't stop laughing, edging through the tunnel, the bats flying hither and thither just inches or closer from me. Of course if this had been a horror house film I'd be running away flailing my arms around, but I knew they weren't interested in me and just want to get to their destination so I edged forward just enjoying their simple presence even though I couldn't hardly see them.

Then oddly, I realise that I had another question for the attendant. I thought about shouting but knowing that would be wrong, I turned on the spot and retraced my steps noticing that the school group has already left - I'd been so enchanted by the experience I probably hadn't heard the fear of the children. The attendant is still there, and I think I made her jump as I approached, which you'd think was impossible considering where she was standing.

I asked her about the names, Roderigues and Livingston. Who where they? Roderigues is the place they're from, Rodrigues Island in Mauritius. Livingston was the naturalist who discovered them. I thanked her again and wish her well and then walk back, more briskly this time. I'd decided I had the measure of the bats now and smiled as I watched a couple entering the tunnel in front of me knowing already what they were about to get themselves into. Sure enough, he swore. Loudly.

On the other side of the tunnel I was already very close to the exit. But I didn't want to leave yet. This was the most exciting thing that has happened all day (the jaguar included) and worth the price of the admission on its own. I watched as more people streamed in, some having the same reaction I did as they realise that the bats are just as close to them as pigeons in a town square. I looked down again at the pool and notice the surface skin break now and then. Bat droppings?

I looked around and saw two Roderigues bats in a rare flight, and in unison they swooped (if that's the word for it) and I realised that I was now standing directly in their flight path. Time seemed to low down and I could see the light in their eyes - what if the sign was a lie? What if they do bite or at the very least get tangled in your hair. My body reacted instinctively as though this is something that happened all the time, my knees bent, I ducked and the bats flash over, briefly filling the space where my head had been.

I took that as a hint that it was probably time to leave. On the way out, an information board lists many of the different types of bat there are in the world and most are either critically close to or are already extinct. A collection of reasons, all man related, everything from the destruction of natural habitat to climate change. Outside the clear spell that had been promised on the weather that morning had arrived and I squinted in the sunlight.

I decided that some of my prejudices about zoos had been nullified. They're not perfect - even here, to this layman, some the enclosures seem far too small for the beasts within and all too often I'd notice a deer or whatever that had obviously walked the same route through the dirt for hours, creating a pathway, and the lions in particular looked defeated, simply lying together on a promontory waiting for dusk. But then they could simply have been having a rest after a particularly busy day.

Throughout Chester Zoo there's a conservation message, what the place is doing to save endangered species and the bat house is a working example of that. But the debate about whether survival in captivity is survival at all is something I'll save for another time. For now, as I remember the instant when I saw those bats for the first time, as far as I'm concerned the old slogan still stands: good zoos are good news.