The cat burglars! Experts try to solve the mystery behind feline crime sprees

The thieves went for particular items. Day after day, they roamed the neighbourhood and returned home to dump their loot. Before long they had amassed an impressive haul: socks, underpants, a baby's cardigan, gloves and yet more socks.

- Ian Sample

It is not unusual for cats to bring in dead or petrified mice and birds, but turning up with random objects is harder to explain. Researchers suspect a number of causes but tend to agree on one point: the pilfered items are not presents.

"We are not sure why cats behave like this," says Auke-Florian Hiemstra, a biologist at the Naturalis Biodiversity Center, a museum in Leiden in the Netherlands. "All around the world there are cats doing this, yet it has never been studied."

The clothing crime spree, perpetrated this year by a mother and her two offspring in the small town of Frigiliana in southern Spain, has made neighbourly interactions somewhat awkward for their owner, Rachel Womack. But for scientists such as Hiemstra, it has provided fresh impetus to study the animals.

"I want to know exactly why they do it," he says. "And documenting cases like this could be the start of more research in the future."

klepto-cats Hiemstra heard of the from the Dutch visual artist Anne Geene, a friend of Womack who mentioned the cats' antics. Intrigued, Geene flew to Spain to photograph the haul for a book, Low Hanging Fruit. Hiemstra, who studies the contested ground where animals and humans collide, wrote an introduction, noting: "This is their collection, their criminal record. But why would a cat collect such trophies?"