The bone man: A skull collector reveals his extraordinary private collection

Alan Dudley is the owner of probably the largest private collection of animal skulls in the world. In his new book, Simon Winchester explores an extraordinary hobby.

Alan Dudley is one of a rare breed of specialists who select and treat wood veneers for use in the interiors of very expensive British motor cars. That's his day job. After work, he collects skulls.

As with many obsessive fascinations, his hobby began by chance. In common with most small English boys of his generation – Dudley was born in 1957, in Coventry – he was fascinated with wildlife: he collected birds' eggs and kept newts in a jar.

One day soon after his 18th birthday, he found the carcass of a dead fox draped on a garden fence; he took it home, with a view to cleaning and studying it.

By the time he collected the animal, it was little more than a ragged mess of fur draped around a core of skeletal bones. He dismounted the head, took off the fur covering with a knife and tweezers, and got his first good look at a whole skull, magnificent in its purity and perfection.

He learnt the various ways of preparing a skull. Some collectors, having performed the rough cleaning with knives, employ flesh-eating maggots to nibble their way around the crevices.

But Alan Dudley found that the maggots were too brutal in their treatment of some of the finer bones, distorting them in their eating frenzy. So Dudley's preferred method is cold water maceration: basically, soaking the new-found skulls in a bucket of water for a very long time and letting any still-adhering flesh dissolve away, with help from the bacteria that find their way into the bucket.

The process is extremely smelly and very time-consuming. But after weeks or months submerged in water that becomes dark and perfectly horrible to be near, the blood vessels, the bands of cartilage and clumps of muscle, as well as the eyes and tongue and soft palate and hearing mechanisms, all vanish, and what remains is an off-white amassment of curvilinear bones that can be washed and whitened with hydrogen peroxide to be labelled and placed in a display case for the remainder of time.

Over the years, Alan Dudley became an extremely accomplished skull collector. He was well known in some circles, seen as an authority. He soon began dealing with nearby zoos – curators would call him if one of their animals died. He began trading skulls with other collectors, both in Britain and in the United States.

When Alan Dudley started trading skulls over the internet, he was well aware of all the various international laws covering the exploitation of some kinds of animals; aware that endangered species were taken illegally and plundered for various parts that fetched stellar prices in particular corners of the world. But he had long supposed that his collection conformed in all ways with legal requirements and restrictions.

Which is why Dudley was more than a little surprised when, one March afternoon in 2008, four police officers arrived at his door, including a wildlife crime officer and an enforcement officer from Customs and Excise. They came with a search warrant, so Dudley had no choice but to let them carry out a lengthy inspection of his enormous collection.

While the police found that the majority of the collection was entirely legal, some specimens had clearly been bought in disregard of the law. Dudley was eventually charged with a crime: with seven counts of having breached CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora). The skulls that most exercised the courts were those of a howler monkey from Ecuador, a penguin, a loggerhead turtle, a chimpanzee, a Goeldi's marmoset from Bolivia, and a tiger.

He was ordered to wear an electronic tag – calibrated so that it prevented him from having access to his collection, which had crime-scene tape strung across the door. And when the case went to Coventry Crown Court, where he pleaded guilty, he was sentenced to 50 weeks' prison time, suspended, fined £1,000, with £1,500 costs, and the specimens at the centre of the controversy were confiscated. The judge in the case spoke of an "academic zeal" that had "crossed the line" into "unlawful obsession".

Once reunited with his remaining collection, Dudley vowed to be more cautious in his purchasing practices, less impetuous in deciding to buy some of the rarer species that he still needs to expand his world-class collection.

Yet Dudley remains sturdily enthusiastic about his curious obsession. He reminisced about his earliest – and to outsiders, somewhat grotesque – triumphs. He tells of finding the body of a tethered and starved Great Dane in a dilapidated apartment complex in Spain, and cutting off its head with a penknife; of the tortoise his mother had buried in a plastic bag and which had turned entirely to mush; of a hedgehog he found, with which children had been playing football and "yet with its nasal bones still not damaged by the roughness of their game"; of how his then-wife Jacqueline vowed to destroy his entire collection because of the dreadful smell of a rotting green iguana; and of how, when he saw a spider monkey that had died of cancer, "I couldn't bring myself to take her head, so sad was her story".

Extracted from 'Skulls: An Exploration of Alan Dudley's Curious Collection' by Simon Winchester, with photographs by Nick Mann (Black Dog & Leventhal). To order a copy at the special price of £17.95 (usually £19.95), including p&p, call Independent Books Direct on 0843 0600 030