The Hidden World of the Fox

When people exclaim that foxes are everywhere, they are both correct and imprecise. The Mammal Society’s National Mammal Atlas shows fox records in nearly every British grid square, from Cornwall to Sutherland, the Cambridgeshire fens to the Western Highlands. They are absent from the remotest islands, but mainland Britain is unquestionably the domain of the fox.

Not to an even degree, however. The weakness of a simple presence-absence map is that it gives the impres­sion that all landscapes are equal. In reality, of course, some places have far higher fox densities than others. No one considers it surprising that humans are clustered tightly in cities, with only a smattering of houses in moor­land. In one sense, the fox population also has its high-rise flats and hamlets. All land is not alike.

‘DESERT FOX!’

My guide, a khaki-clad middle-aged Indian of mili­tary bearing and Sherlockian skill in tracking all creatures wild, spins the steering wheel of our jeep. Dust spurts, the vehicle’s suspension lurches, and behind us lie treadmarks in the white, white dust. Ahead, no doubt, there is a fox; but mostly there is nothing, as only the desert knows it. Vast flat horizon and vast, vast dusty sky: a land crossed by Rabari tribals and their cattle, but immune to the modern world. I am in the Rann of Kutch in India’s Thar Desert, rattling across the dry ancient bed of the Arabian Sea. I have travelled to many remote places, but this is a land­scape apart: seasonally cracked in fiery heat, swamped by monsoons, bleached by salt, and blurred by mirages – stark, wild, beautiful and brutal.

Crossing India’s Rann of Kutch, part of the Thar Desert.

The jeep has stopped.

A fox looks up at me.

It is sitting in a scrubby thicket of what the local people call toothbrush bushes, amber eyes so clear and sharp. It is a red fox, Vulpes vulpes; just like those in London, although its fur is straw-coloured, as if irradiated by the Gujarati sun. It is a curiously sobering thing to observe a fox in an over­poweringly enormous landscape – a theatre refined by torrid heat until it retains only the core essentials of grit and sky. They, too, are raw and unhumanised, and their basic needs cleanly defined.

What is actually needed for survival? We ask that question of ourselves in Robinson Crusoe and its modern spin-offs, but applying it to wildlife may remove the con­fusion over seeing a fox in the very heart of the metropolis. A hypothetically shipwrecked fox would probably thrive, for its needs are very simple: some shelter to evade weather and enemies, and about 120 kilocalories per kilogram of bodyweight per day. That equates to about nine voles or one rat daily – or one double cheeseburger with fries. Even the bleakest of our cities offer sustenance on this scale to a scavenger-hunter.

The cracked dust of the Gujarati desert does sup­port some hardy plants, which in turn feed herbi­vores. The desert fox may seek exotic-sounding rodents such as the golden bush rat, the jird, and the Indian gerbil; insects, and the carrion left behind when wolves or ja­ckals kill chin­kara gazelle, are also possibilities. Those little th­ickets of tooth­­brush bushes – known as bets – offer shelter from the murderous May sun and stay above the waterline during the monsoon floods. Nothing more is required. How­ever improbable it may feel to a human figure dwarfed by a blood-red sunrise, watching wild asses gallop across bone-dry salt flats, this land is perfectly suit­able fox country.

On the other hand, so is the ancient forest of Białowieża in Poland, where bank voles scurry past gigantic fungi and wolves inadvertently provide a regular feast of wild boar carrion. So are the gloriously wild prairies of southern Canada, where a bewildering array of rodents whistle from meadows painted glittering silver in springtime ice storms. And so most certainly are suburban British gardens, where they may have their weekly calorie requirement handed to them on a dogfood dish every single night.

The abundance of potential food in each of these habi­tats is different, however. There is no ‘normal’ or ‘cor­rect’ fox population. Each area is unique. Even the subtlest local changes can trickle upwards – in the harsh moun­tains of northern British Columbia, for example, areas dominated by lichens are avoided by foxes in favour of those where goat willows are found. In Belarus, forests growing upon clay soils support more prey than those on sandy de­posits, and have higher fox densities. How many journalists musing over British fox numbers have thought to take samples of the local soil type?

Obviously, the more food available, the more foxes that the area can potentially support. As a general principle – and notwithstanding countertrends driven by disease and the impact of natural competitors like badgers and coyotes – foxes are distributed unevenly across their huge natural range because food itself is uneven. By that yardstick, the Strand may be even harsher than the Thar Desert; yet both have their foxes. So do the Himalayas, the sub-Arctic, the rainy Spanish mountains and Edgware tube station.

At this point, it is worth taking pause. Think of the world’s most famous animals: tigers, elephants, koalas. How many exist in a range of habitats even close to the diversity of the fox’s natural homes? Range expansion is one of the fox’s rewards for being unspecialised.

Improved odds of beating extinction are another. Replacing wildwood with cold London stone devastated many of our native species, but the fox has survived – and often thrived – during all our changes to the British landscape. A clue as to why comes from the enchanting knife-edged mountains of Sichuan in China; unlike the giant pandas that also wander this landscape, Sichuan’s foxes do not risk starvation when a single food source fails. The panda, famously, is a specialist consumer of bamboo. Should this plant flower and die, as stands do on a regular basis, the panda must move to a new area or perish. Not the fox with its catholic tastes; if, say, its stereotypical Brit­ish prey of field voles runs short, it will simply switch to pouncing on wood mice or rabbits instead.

Nor are they specialised to a specific habitat. Otters can be wiped out from an entire district by river pollution. A fox population, in contrast, covers so many habitats that even if it faces an environmental disaster in farm­land, it will persist in the neighbouring wood, and soon re­colon­ise.

Wherever it lives, a fox learns an acute carto­graph­ical knowledge of its local landscape and explores it at a purposeful-seeming trot. In the Swiss Jura, foxes travel about 4 to 12 km (2.4 to 7.4 miles) daily; interestingly, their kin in a residential district in Toronto, Canada, have wider extremes, varying from 2 to 20 km (1.2 to 12.4 miles). Urban Canadian foxes are provided with far fewer deliberate handouts than their British counterparts, how­ever, so source a large percentage of their meals directly from the land.

While foxes have allegedly been clocked at 50 kph (31 mph) in short bursts, their typical pace is far slower, and punctured by rest periods in which the fox will doze under a hedgerow or in a quiet urban corner. The Swiss foxes aver­aged a speed of about twelve metres per min­ute, although one individual, who was a transient – a fox without terri­tory – moved considerably faster. While all this may seem like a considerable exercise regime, it is far below the 26 km (16 miles) averaged by male wolves per day. Individuals of both species that are dispersing from their parents into a new territory can wander much fur­ther.

One persistent piece of fox folklore is that they are noc­turnal – that is, active by night only. Sometimes, this myth slips into the medical department via warnings that a fox enjoying the sunshine must be ill. In fact, it is no cause for alarm. Foxes do pursue a nocturnal existence in regions where they are heavily persecuted, and, as is the case for many human-caused aberrations to the natural world, we have grown accustomed to this atypical state of affairs and convinced ourselves that it is normal. Left to their own devices, foxes will adapt their activity patterns around their social and food-gathering needs. In the world’s great wildernesses, from the Thar Desert to the boggy forests of Ontario, foxes are easily found abroad during daylight hours.

Foxes are often active in daylight where they are undisturbed.

In Britain, field voles tend to be diurnal – day active – if the temperature drops below freezing, and foxes, and indeed barn owls, naturally follow suit. Needless to say, if they find a person who regularly feeds them pork saus­ages in daylight, they will adapt their activity around that food source instead. I have also known several low-ranking foxes that opted for daytime travel to avoid confrontation with dominant individuals.

Radio-tracking has shown that the daily wanderings of a territory-owning fox fall into two distinct types. The first is a circumnavigation of its entire territory, and the second – and more common – is of visits to different parts of their range each night. Varying their journeys gives them the optimum chance of exploiting food resources; if they were to concentrate on the same field month upon month, it would eventually run dry of voles while the untapped pas­ture half a mile away is awash with them. It is worth adding that the enormous bounty provided by people who feed garden foxes has added a third trend: foxes who travel little and appear in sizeable numbers in specific sites every day.

Under more natural conditions, foxes tend to cross the landscape in a large-scale zigzag pattern. They are often religiously loyal to specific routes, wearing narrow paths into grass through repeated trampling. In the wilderness, they climb onto fallen tree trunks and walk down their full length as a kind of elevated track; in Britain, they occasion­ally exploit railway lines instead. Last year, I was shown some startling footage of a fox in Wales trotting briskly down a train rail hardly wider than a human hand, bal­ancing like an expert on a tightrope.

Railways and foxes often occupy the same sentence. While human commuters frequently feel that our rail net­work is more of a hindrance than a help to travelling, it is commonly stated that our vulpine neighbours are trans­ported by them. Not as passengers – although there are several credible accounts of urban foxes jumping on board public transport – but rather as walkers along the banks. Even at those moments when the Gatwick Express thun­ders past the East Croydon congestion at 100 mph, and on just the other side of Network Rail’s perimeter fence, millions of people shop, argue and check their phones, the embankments themselves remain one of the least dis­turbed environments in the city. It is often said that foxes first immigrated to London in the 1930s, the pioneers moving down railway lines into this new brave world full of human creatures.

But when talking of the arrival of fox in city, it is as well to remember that city has also travelled extensively into the traditional land of the fox. London has bloated mas­sively over the last two centuries, and despite the best efforts of greenbelt campaigners, continues to do so. Many of today’s ‘urban’ foxes may be descended from ‘rural’ foxes whose habitat was suddenly turned into hous­ing estates. Incidentally, records of foxes near towns in Fin­land date back to the medieval era, and their distinct­ive barks were heard in Tokyo in the ninth century. There is even some suggestion that foxes scavenged on abandoned scraps from humans as long ago as the Palaeo­lithic – the Old Stone Age.

Regardless, considerable research has taken place in recent years to establish the impact of railway lines on fox densities and movement patterns. But evidence that dis­persing foxes, and indeed territory-owners on the hunt, are funnelled by the railways is also remarkably scant; radio-collared foxes have shown little preference for the train lines.

Taking the wider view, why would they? Humanity has proved tragically skilful in fragmenting the habitat of hedgehogs, toads and dormice, but foxes are much more capable travellers. They can and do cross roads, car parks and fences. Even the natural world’s topography has little impact; genetic sampling from Croatia has shown that they migrate freely across rivers and small mountains.

When not travelling or feeding, foxes require a suitable place to rest. This may be anywhere within their home range, even close to the territorial border. Foxes have more than one den, including sites that may only be used temporarily. Researchers in Polish farmland found that earths tended to be dug on steep south-facing slopes, with western exposure avoided, possibly due to the prevailing westerly winds. In suburban Britain, foxes often rest on greenhouse roofs or sunbathe in quiet alleys. I’ve found one stretched out contentedly on warm plastic in a narrow gap between a wall and a garage, peaceful and safe, despite being within metres of a major supermarket car park used by hundreds of humans each day.

BUT THE STRAND is crossed by thousands upon tens of thousands of people. Even at midnight, it is alive: lights on the arching stonework, music thumping from cars as they choke in bus-filled traffic jams. I’ve come back here because I want to better understand the miracle of foxes in a desert of towering grey rock. Friday night has spilled people upon the streets, shouting, selfie-taking, watching buskers batter their drums. More of them sprawl between the paws of the giant lions of Trafalgar, strangely drawn to the cold stone models of wild animals. Night itself seems defeated by the battle squadron of lights jumping upon these grandest of buildings, reflecting on the river, luring punters into shops. So it continues on the journey south­wards: shuttered shops, drunken youths, urban cries and urban dreams.

There is a fox.

A male, all long limbs and thick brush, sits on a patch of grass under one of Brixton’s tower blocks, half illumin­ated by streetlight. He turns his head towards the car as we pass, watching, just like his kin in the silent and utterly wild Thar Desert.

Adaptability.

That, in essence, is the fox’s gift.

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What Does the Fox Look Like? (#ulink_4b98be42-2e3a-5b97-8fe7-785935fde6e0)

The world is full of magic things, patiently waiting for our senses to grow sharper.

W. B. YEATS

IN A LONELY ARABLE FIELD in eastern Surrey, the North Downs Way National Trail and the Prime Merid­ian collide in a crossroads perfectly aligned to the points of the compass. To the south lies the ceaseless rumble of the M25 and its luxurious trim of rolling green countryside. Northwards rises the chalky ridge of the Downs – due north, in fact, and I know this from my map and the pos­ition of the sun. But if I were a fox, my navigation might be written into my physical senses.

Slightly offset from true north, the Earth’s magnetic north pole drifts each year due to the behaviour of molten iron in the planet’s outer core. The invisible magnetic field that envelops our planet protects us from harmful cosmic rays while also playing host to the geomagnetic storms that produce spectacular auroras: the northern and south­ern lights. It has had a profound impact on human his­tory, because compasses – those aids to explorers, traders and armies for millennia – only work because their magnets swing to the poles, where the field’s inclination is vertical.

The geomagnetic field and its poles also have very real significance for animal behaviour. Birds may navigate by it, rats become more restless during magnetic storms, and some researchers have argued that resting cows tend to align themselves pointing poleward, except under power cables which locally disrupt the field.

And foxes, perhaps, hunt by it.

Imagine that you need to catch a rodent in dense cover. The rodent, naturally, does not want to be caught, and is equipped with formidable defensive senses of its own. It may also have awkward behaviours; bank voles, for ex­ample, reduce their activity upon detecting fox scent, for the rustles of their feet on vegetation are, perhaps aptly, their Achilles heel. But hearing may not be the fox’s only means of pinpointing its target.

A fox that is stealthily approaching its intended meal will be most successful if it orientates itself either within about 20 degrees of the magnetic north, or due south, at least according to one recent study. Leaps from other directions usually fail to pin the prey. If foxes are indeed capable of magnetoreception, the mechanism by which they perceive the direction of the magnetic poles is un­clear. The authors of this study speculate that foxes per­ceive the geometric field as an area of light or shade in their vision – in fact, even in people, laboratory tests show that the field impacts light perception.

Foxes may use the directional information from the magnetic field together with auditory input from the vole’s rustling to move to a fixed distance from the target, allow­ing a precise leap. If so, foxes are the first species known to use the magnetic field as a measure of distance.

THE PHYSICAL FOX – the frame that supports this curi­ous, intelligent, beguilingly strange canid lifeform – is complex. That frame is aesthetically pleasing to many human observers, but our perception of beauty is ir­rele­vant to the creature itself. It is the demands of survival that have whittled the fox’s senses, size, bone structure, brush shape and teeth.

What has emerged is almost the perfect formula: a carni­voran that is omnivorous – a generalist – yet which still carries a specialist’s trump card. As we have already seen, the fox can survive almost anywhere, and on a mind-bogglingly diverse array of food; but for all its catholic tastes, it has never lost its finesse in hunting rodents. Much of what we admire about the fox is a direct adaptation to the challenge of catching such small, swift prey. In a very real way, foxes are built around mice.

It is part of their bones – especially in North American foxes, which have limbs considerably lighter than expected for a canid of their size. A light frame with a small stom­ach can be launched with ease at a rodent-sized target. The huge tail aids balance.

Foxes are guided by their hearing, which is sensitive to a degree that human imaginations might leave short. Every winter I observe foxes hunting field voles in frosty meadows, weaving slowly through quiet tussocky grasses in a gentle amble so different from a travelling fox’s precise, purposeful trot. One morning, I was watching a hand­some russet fox in a sloping field, when he veered sharply to his left, tilted his head – raising one ear canal above the other to better pinpoint a sound’s position – walked about 6 metres (20 feet), and pounced on a rodent.

A fox can hear a much wider range of frequencies than us; their upper range is similar to a dog’s, while the lower range is comparable to that of a cat. Their eyesight is much weaker than ours, but photographing a fox at night with a flash uncovers one of its ocular secrets. Unless you are very careful or fortunate, the resulting image will feature a coloured washout of the animal’s eyes. The culprit is the tapetum lucidum, a remarkable layer of tissue directly behind the retina. Present in many creatures that are active in low light levels, from fish to tigers, it reflects visible light back through the retina, effectively brightening the world for its owner.

A fox sees, smells and hears the world very differently to us.