Instead of being out with the lads on the weekend, Somerset sixth-former Max Blake can be found tramping the countryside, photographing mutilated carcases of sheep and deer, and searching the ground for tell-tale paw prints.

At 18, Max is surely Britain's youngest mystery big cat hunter – at present, his investigations are centred on Stoke St Michael, near Shepton Mallet, where a black leopard-like creature has been seen and there have been numerous livestock kills in recent months.

"I try to go out every week, or once a day for a series of days," Max told me. "I take photos of any sheep killed, look around for any tracks, and keep an eye out for anything that could resemble a big cat."

Max, of Wells, who attends the city's Blue School, became gripped by the big cat mystery in November after reading in the Western Daily Press about farmer John Chislett who had had 30 sheep killed in just over a month, and who wanted some help in verifying the killer as a big cat.

"He had seen it alone more than once, and had seen a pair, one larger than the other, once," Max told me.

"A paw print was found, and by the description he gave me it fits a large cat, possibly puma, possibly leopard. I photographed what I could see of the kills and went up to the field repeatedly to work out what was going on."

Then, in December, Max heard a big cat had been seen moving across the Mendip shooting ground nearby.

"The cat had walked through a field and on to a small private road where it was seen at a range of only 20 yards by three people in a car," he said.

"Obviously, I went up there as fast as I could to talk to the witnesses. They described it as being black, slightly larger than an Alsatian, fairly low to the ground, having a very long tail with a curl at the end and moving in the typical cat's slink. This, particularly the tail, would suggest it was a leopard."

Max believes the cat was pushed into the area by the local fox hunt, and then set up residence in woods nearby. Max stationed a trigger camera in the corner of a field – but there was a setback when the equipment, worth about £100, was stolen.

A s to the nature of the mystery beast, Max's opinion is down to earth. "There are big cats in Britain," he said. "They're real, they're living. They are not being transported around by UFOs or any form of magic, or shifting dimensions, as some theories go.

"The first records of them being here date back to the 1800s, probably from travelling circuses which brought exotic animals from Asia and Africa and there were escapees."

Max also holds the commonly held view that the Dangerous Wild Animals Act of 1976 caused a number of big cats in private ownership to be released into the countryside. But how did he account for the hundreds of sightings of big cats now being reported every year throughout the UK? "Lots of cats!" he laughed. "I'd say that they are breeding.

"We wiped out the big predators that used to live in Britain – bears, grey wolves, lynxes. There's still a place for a top carnivore and these animals appear to be taking that job."

Max, who plans to study zoology at the University of Bristol from next year, has a home menagerie which includes exotic fish, beetles, cockroaches, spiders and scorpions.

He is one of the youngest members of the North Devon-based Centre for Fortean Zoology, which he found out about and joined after he subscribed to Exotic Pets magazine, published by CFZ.