Foxes, Cats and Occam’s Razor

Or: why Sherlock banished emotion while solving mysteries.

Foxes have been in the news again, which is one of those things I dread. It is a mystery of the universe how a very small and mostly harmless carnivoran morphs into a ginger Cerberus whenever it encounters the tabloids, but to summarise:

1. The UK has about eight million pet cats (RSPCA estimate). Sadly, on any given night, some of them are statistically likely to die, especially if they are permitted to roam outside unsupervised. The great outdoors is not safe for cats. There’s cat flu, feline immunodeficiency virus, garden pesticides, and most of all, the motor car.
2. Foxes, which for countless millennia have consumed carrion left behind by wolves and lynx, readily scavenge on these dead cats.
3. Somewhere along the line, an animal rights group examined the bodies and concluded that a very nasty human psychopath was beheading, mutilating and dumping cats to torment their owners.
4. Social media spread this theory like wildfire. The awards for catching the Killer grew higher. Sensational claims spread on and on and on, including that the Killer had started stabbing foxes as well (quite how he hand-caught an animal that can leap over a six foot fence, run at 50 km/h, and will bite in defence if cornered, was never explained).
5. Our beleaguered police got dragged in and spent years, and unknown thousands of pounds of taxpayer’s money, and discovered…that foxes scavenge dead animals.

As a fox advocate and ecologist, this sad episode is one that I could have done without. The media immediately leapt on the idea that foxes are hunting cats, which is not actually what the police said. The post mortem evidence quoted clearly shows that the causes of death were blunt force from a vehicle and the ‘mutilations’ (actually, innocent scavenging) took place afterwards.

For what it is worth: a healthy adult cat is at no risk from a fox, which is primarily a predator of voles, earthworms and berries, after all. Kittens and very elderly cats may theoretically be more vulnerable to all the risks of the outdoor world. But every day, millions of cats encounter foxes, and the normal outcome is for the two species to ignore each other – check out my video here. However, cats can and do attack foxes on occasion.

As a scientist, the lack of objective thought truly bothers me. It should have been obvious from the outset that something was very wrong with the Cat Killer theory. A five minute conversation with a mammologist would have confirmed that foxes and dogs have carnassial teeth that leave cutting marks similar to knives. The logical implausibility of the Killer evading so many CCTV cameras, pet owners and police officers should have rung alarm bells.

As a human being, I feel real anger that hundreds of pet owners were persuaded that their beloved animals suffered a miserable end at the hands of a violent criminal. Can you imagine if your grief was intruded on by a suggestion that a human monster had done this terrible thing to a living creature that you loved?

Facts, matter.

Testing evidence with cold-headed objectivity, matters.

People are often accused of wanting to believe that things are better than they are. But it is surprising how often we choose to believe that they are worse. In North America, fishers are  often viewed as wanton cat killers (spoiler: they’re not). In the Andes, the tiny mountain cat is feared as bat luck; it’s aye-ayes in Madagascar, and magpies in the UK. Why do we want to be scared? I can name a town in British Columbia that shot five black bears one summer not because they were threatening anyone, but, well, it’s better to be afraid.

Sometimes – just sometimes – it isn’t.