Dom Joly: Now I'm a zoologist, my furry costumes are specimens

Two days out of Dushanbe on horseback and my buttocks are bleeding. We are an expedition of six riders and three armed soldiers . They accompany us periodically before disappearing into the surrounding Kush for hours on end. As they look like men who would have no compunction about killing, I hope that it will be a would-be attacker and not us who gets to find out.

I arrived in Tajikistan on a particularly bumpy and uncomfortable flight. The man sitting next to me appeared to have decided to see if he could break the little known Guinness record for consuming garlic in a single sitting. Using the tiny synthetic pillow, I attempted to smother myself for most of the flight.

I am here to research my next book, Scary Monsters and Super Creeps. In it, I become a cryptozoologist (monster-hunter) and try to find some of the world's most elusive creatures.

There have long been rumours that, on the border between Afghanistan and Tajikistan, there exists a Central Asian yeti, known as the almas. Reports tell of the beast slaughtering livestock as well as supposedly abducting children from several villages. We are off to investigate.

We ride through the rocky, mountainous landscape for hours, spotting the occasional goatherd staring curiously down at our little convoy. I start out in jeans and T-shirt but, after considerable chafing of the nether regions, I succumb to local dress.

I have a rough beard, smell of horse and onions, and have the dust equivalent of a ski-goggles tan. Should the US army send a snatch squad over the border and come across out ragged little band, I fear that it will be quite some considerable time before I see the light of day again.

No matter how many times I attempt to explain to the interrogators at Bagram base that I am a British comedian in search of a mythical hairy man, I don't rate very highly my chances of avoiding an extended holiday in Cuba.

Our destination is still three days ride away and every night we camp beneath the glorious canopy of stars. The expedition cook, Sufa, is a culinary whizz with entrails and we have eaten the slowly roasted innards of myriad creatures. All this is washed down with a bowlful of a warm, milky substance. From my travels in Kazakhstan, I believe it might be mare's milk and have opted to go with this rather than risk any more frightening revelation.

The almas is supposed to be a tall, hairy, ape-like creature that emits a throaty howl and smells to high heaven. For them to survive here there must be several, and locals all speak of the creature with a familiarity that indicates we just might come across something. At night, I have anxiety dreams about finally coming across one of the creatures only for it to rip my throat open and start to gently roast me on our own campfire.

Occasionally, I dream that the whole affair is simply a linguistic misunderstanding and that our proud guides eventually bring me, and my haemorrhaging buttocks, face to face with a small mountain goat.

In a way, that might be a better conclusion than actually finding the beast. One of the unique problems that I face as a cryptozoologist is my background as a prankster who specialises in jokes involving large furry costumes. If I return to the UK brandishing photographic proof of some hairy beast, who is ever going to believe me? I really didn't think this whole thing through.