It can get a bit nippy in this tropical paradise...

... if, like me, you get bitten by a sand crab, says Cathy Pryor. But not all the wildlife are unfriendly in Thailand. Plus you can split your time between sunbathing and rather more adventurous activities

It was a bit like Satan turning up while you're telling a ghost story. There I was, up to my neck in water as warm and soupy as a bath, a hot blue cloudless sky overhead. Strange, unseen birds gave harsh exotic cries; palm trees from central casting obligingly dotted the nearby white beach. It was a peaceful, perfect afternoon on a tropical island which we felt we almost had to ourselves. Clearly, when you're in the sea, there's only one sensible way to pass the time: talk about shark attacks - the gorier the better. I was nearing the climax of the most gruesome tale in my repertoire. What do you think happened next?

It was a bit like Satan turning up while you're telling a ghost story. There I was, up to my neck in water as warm and soupy as a bath, a hot blue cloudless sky overhead. Strange, unseen birds gave harsh exotic cries; palm trees from central casting obligingly dotted the nearby white beach. It was a peaceful, perfect afternoon on a tropical island which we felt we almost had to ourselves. Clearly, when you're in the sea, there's only one sensible way to pass the time: talk about shark attacks - the gorier the better. I was nearing the climax of the most gruesome tale in my repertoire. What do you think happened next?

My shriek of fear and pain galvanised my companions, who cried out in alarm. There was something in the water! "It bit me!" I bawled. Panicking mightily, we lurched back to shore, the wounded (me) straggling nobly hindmost. The cry went up: "there's been an attack!".

Er, well, sort of. There are sharks in south Thailand, but you'd really be quite unlucky if they turned you into breakfast. Along with the region's outstanding tropical beauty, its fiercely hot climate, its sumptuous beaches, you'd expect some nasties: jellyfish and stingrays, to name two critters of which swimmers should be aware. But if you thought it was safe to go back in the water, you're largely right. I'm sorry to say that the bite I got was from nothing more frightening than a sand crab. I never saw it but I think it was about the size of my little fingernail. The whole incident was really about as dramatic as a gentle gin and tonic in the late afternoon - though I did yelp rather more loudly than dignity allows. I will say two things about my terrifying attacker, though: it gave an almighty nip for its size and it had the comedy timing of an Eric Morecambe.

It may not sound like it, but Thailand's wildlife is one of the many reasons for holidaying there this winter. We flew in through Bangkok and spent most of our time in Trang and Krabi provinces on the western side of the Isthmus of Kra - the long, skinny peninsula just above Malaysia. We also visited Ko Yao, (Ko means island) in the Phang Na Bay. Some parts of the south, such as Ko Samui and Phuket, are very commercial, Trang and Krabi are relatively untouched. Along with the unspoilt scenery - the tropical islands, rainforests, beaches and coral reefs - the region includes several wildlife sanctuaries and national parks. For those who love wildlife as much as they love sunbathing, it's ideal.

Let's give the crabs their due. As you're walking barefoot along the beach, palm leaves tossing overhead and the hint of a coming storm galvanising the moist, oppressive air and tingling the hairs on the back of your neck, it's entertaining to see the tiny white crabs rearing as if they were going to cartwheel out of your way. And I can't really hold the nip against them because they weren't the only ones - some fish I tried to feed in the Andaman sea near Krabi took a piece of me as well (a conspiracy, perhaps?). That was fun, too: dozens of luridly pretty blue and yellow striped fish recklessly piling across my hands in the water to snatch a chunk of croissant, scraping (mostly) harmlessly at my fingers with their tiny teeth.

Not all the animals bite you. Kayaking through a mangrove swamp at Krabi we came upon a family of monkeys, including a tiny baby, in a tangle of branches no more than a couple of feet above our heads. They didn't look menacing: in fact, they looked distinctly bored as if we were the unwelcome aunt and uncle no one wants to see at Christmas. They sat, passively gazing at us, so close, so composed. Then there were sea eagles that floated out unexpectedly from a high cliff, far above us. Back at the beach, there were fat, fleshy starfish half an arm long dotted lavishly about in the water and two huge monitor lizards strolled by, flicking their long blue tongues in and out while we were having lunch on the sand. I also saw a mystery bird - a big clumsy creature clattering down through the air towards a palm tree, its black shape outlined against a high tower of pink clouds at 6am. The sweltering heat had meant I couldn't sleep. I still don't know what the bird was: but I did know a kingfisher when I saw it, sitting on a power line, its back intensely blue in the sunlight.

The creatures you couldn't see you could certainly hear: the deafening chorus of hundreds of frogs that started up after sundown on Ko Yao, crickets chirping in your roof at night, hornbills giving harsh calls close by in the afternoon. If you visit Ko Muk, near Trang - a hollow, rocky cone of an island whose interior can only be reached by swimming through caves at low tide - you will find inside a tiny beach. It feels prehistoric, forgotten long ago by the rest of the world. The only sound apart from the waves is the bats - hidden among long trailing stringy plants, their rattling croaks rising to an eerie glaring drone like a dentist's drill.

However, there is plenty to do in the region besides admire the wildlife. Scuba diving, snorkelling, rock climbing, sailing, sea kayaking, visits to fishing villages, elephant rides through the jungle. And there's indoor stuff - yoga, massages, cooking classes, Thai language lessons. But the beauty of it is that you can experience much of the region's charms while just lying on the beach - you barely have to move. I recommend just relaxing and contemplating the spectacular views - bound to include half a dozen nearby islands rising steeply out of a violently blue sea, sheer cliffs topped with a riot of tangled vegetation. Be careful though: the Thai sun is fierce, and it's all too easy to burn. Between November and March the weather is mostly dry but it can rain equally fiercely. Yet even the storms are fun. It's tropical rain - moody, forceful, energising and quite unlike the limp damp of an English winter.

I have two reservations about travelling to Trang, Krabi and Ko Yao. One is whether resort development will one day overtake this region, as has happened elsewhere. The other is the ecological cost of air travel; I wish there was another way. There is the case of the Belgian man who was so much in love with tuk-tuks - the tiny open-sided taxis found in Bangkok - that he drove one back from Thailand to Belgium via India, Nepal and Pakistan. A bit extreme for most tourists perhaps.

That said, there are so many good reasons to go. Here's five more: Thailand has independent spirit and an interesting history - when it was threatened by the European colonial powers in the 19th century it had the wit to resist with a little cunning diplomacy; its traditional architecture is frequently stunning; the people are, in general, charming friendly and hospitable; Thais know how to relax (I've never had a better massage than the ones I had there) and then there's the food.

Whether you're a vegetarian or prefer your wildlife on a plate, Thai cuisine has plenty to offer. Hot red coconut curries, sour prawn soup, green mango salad, pungent shrimp paste; delicious. The bananas are sweet, the pineapples fragrant and, if you're adventurous, what about some red ant soup, anyone? I tentatively sampled another local speciality, wasps roasted in salt. Our Thai minibus driver was overjoyed at my choice: "You will have a wonderful meal!" he promised. I can report back that they were pleasantly nuggety, like chicken crossed with peanuts, and with a spicy tang. Not your usual. A holiday with bite.

GIVE ME THE FACTS

How to get there

Cathy Pryor flew to Thailand courtesy of Thai Airways (0870 6060911: www.thaiair.com). Thai Airways runs 13 non-stop flights a week, from £673 return. From Bangkok, a return flight to Trang costs from £76.

Where to stay

Amari Trang Beach Resort ( www.amari.com/trangbeach) is a large complex on the beach with 138 rooms, many have balconies with sea views, a spa and four restaurants. Prices from £91 per night for a double if you book on the internet. The Paradise at Ko Yao ( www.theparadise.biz), one hour from Krabi by boat transfer (from about £20), sits on the beach. It has 50 studios and villas, all sea-facing, a spa and restaurant. Villas cost from £95 a night.

Further information

Tourism Authority of Thailand (0870-900 2007; www.thaismile.co.uk).