Croydon cat killer: DNA analysis confirms foxes, not humans, were to blame

By Jason Arunn Murugesu Foxes are notorious scavengers Jamie_Hall/Getty Images Between 2014 and 2018, more…

Red fox in an urban street during the early morning sun light

Foxes are notorious scavengers

Jamie_Hall/Getty Images

Between 2014 and 2018, more than 300 mutilated cat carcasses were found on London streets, leading to sensational media reports that a feline-targeting serial killer was on the loose. The fact that the cats often had their heads or tails cut off, as well as the cleanliness of the wounds, led many to suspect human involvement. Others dismissed the suggestion, pointing the finger at foxes instead.

To find out more, Henny Martineau at the Royal Veterinary College in the UK and her colleagues analysed 32 mutilated cat carcasses found by the public between 2016 and 2018. The bodies had been stored by the Hertfordshire and Metropolitan police forces as part of an investigation.

The researchers conducted post-mortem examinations on the cats, as well as CT scans. They also swabbed the cats’ fur to test whether they could find DNA belonging to other animals such as dogs, foxes or badgers.

The police struggled to pinpoint the true killer of the cats because of how different all the carcasses looked, says Martineau. “In our study, there were 13 different combinations of missing body parts, so it was difficult to spot patterns initially.”

Testing for DNA, the researchers concluded that the cats had all been mutilated by foxes after they had died. The post-mortem examination revealed that there was no single cause of death among the cats. They suspect that just 10 of the 32 cats they analysed were killed by foxes.

Meanwhile, eight probably died from natural heart or lung failure, while six probably died after being hit by a vehicle. The findings reinforce the conclusions made by the Metropolitan Police in 2018.

Martineau suspects the reason that many of the cats’ tails and heads were chopped off is because foxes have a weak jaw and scavenge alone. “So they are going to target areas that are easy to remove,” she says.

The lack of blood on the edges of cats’ wounds can also be explained by foxes. “The mutilation occurred after the animal had died so it would not be bleeding after death,” she says.

“It is hard to say how many foxes were involved, I guess, but it is possible this was only limited to one or a few individuals that figured out cats could be food,” says Kevin Parsons at the University of Glasgow in the UK.

“Croydon is on the edge of London so it may be happening due to new interactions and encroachments,” he says. “But it could also be that these are ‘badly behaved’ foxes for the time being and such behaviours will eventually be selectively removed from the population as we remain in contact.”

Journal reference: Veterinary Pathology, DOI: 10.1177/03009858211052661

Sign up to Wild Wild Life, a free monthly newsletter celebrating the diversity and science of animals, plants and Earth’s other weird and wonderful inhabitants

More on these topics: