Badgers, weasels, otters, stoats and more: A guide to Britain’s mustelids

Lithe, opportunistic and with a predilection for poultry, these elusive, often pocket-sized predators have long raised a stink for farmers and gamekeepers, but not all of them deserve such an otterly bad rap, believes John Lewis-Stempel.

A mustelid by another name would whiff as bad. The mammalian Mustelidae family comes in all sorts of shapes, from bulky badger to slinky stoat, but all are carnivorous, with well-developed scent glands under the tail. Or, in plain Anglo-Saxon, their bottoms doth make pongs like stink-bombs.

Brock the badger’s shambling corporeality notwithstanding, Britain’s mustelids are generally long-bodied beings, with short legs and a highly flexible spinal column. Think Tarka the Otter. Or a furry, bendy tube with four flurrying stumps. Apart from Brock and Tarka, our native mustelids are the pine marten, the stoat, the weasel and the polecat. To this pack of six must be added the American mink, now running wild across much of the isles following its escape from fur farms in the 1930s. As pipe-shaped mustelid morphology has low thermal value, the smaller mustelids are compensated by a dense, sometimes luxurious fur coating. As are said mink, the pelts of which once upon a Hollywood time adorned every screen goddess.

The mini mustelids also possess a very active metabolism — a weasel burns as much as 30% of its body weight per day. Their seeking of breakfast, elevenses, lunch, tea and midnight snack is near hyperactive. Mustelids are also beady-eyed inquisitive. Hence ‘ferret about’, the ferret being a domesticated polecat.

The Mustelidae arose about 16.1 million years ago, so must be counted among Britain’s oldest landowners. Paleontological evidence shows that badgers have been snouting about the place for at least 250,000 years. Human interaction with our mustelid landlords has been troubled and ambivalent. We have baited badger and hunted otter. In Tudor times, we employed the weasel as a household mouser, but, more recently, the beast is ingrained in the popular psyche as sly and untrustworthy. ‘To weasel out’ of a situation is synonymous with clever, albeit dishonest avoidance.

Of course, Kenneth Grahame’s The Wind in the Willows (1908) takes a share of blame for this antipathetic attribution, with nice guy Ratty declaring of the reprobate Wild Wooders — chiefly weasels and stoats, mustelids both — ‘you can’t really trust them’. Grahame, however, was reflecting a real countryside problem, the long-running feud between mustelids and the poultry farmer, the gamekeeper and the fisherman. And there you have the nub of our sometimes unchivalrous feelings towards our mustelids: we occupy a similar carnivorous niche. We, as it were, badger each other.

Badger (Meles meles)

The bold black-and-white face stripes of badger are a form of aposematism, a contrasting skin pattern warning potential predators that the wearer is dangerous. Accurately, in the case of Brock/bawson/mister teddy/pate. Males of our largest land predator top 39½lb and those front paws are not only for excavating the hobbity multi-chambered ‘sett’ or rooting up plants (‘badger’ perhaps being derived from the French bêcheur, a digger) — they deal death and offer protection.

European badger (Meles meles) running in pine forest in spring. ©Nature Picture Library

And then there are badger’s fearsome canine teeth. As John Clare noted poetically about the historic so-called sport of badger-baiting:

When badgers fight, then every one’s a foe
The dogs are clapt and urged to join the fray;
The badger turns and drives them all away.
Though scarcely half as big, demure and small,
He fights with dogs for bones and beats them all.

Anthropomorphic badgers are frequent in children’s literature, although their personalities polarise as good versus bad. Grahame’s Mr Badger is endearingly fatherly and gruff, but Beatrix Potter’s kidnapping Tommy Brock encapsulates the agricultural view of Meles meles as a devious devourer of little livestock. In truth, the badger is mainly a nightly seeker of earthworms — slurped like spaghetti — although it will eat almost anything, including hedgehogs and ground-nesting birds and bees. It has a noted nose for peanuts; the animal’s sense of smell is prodigious, being able to sniff out a human at 400 yards.

Mating usually occurs in July, but implantation can be delayed by two to 10 months, with a single litter of between two and three cubs born between January and March. The badger is our most sociable mustelid, living in extended kin groups of two to 20 and performing funeral rites for the deceased. Formerly a confirmed rustic, the badger has extended its range to towns. Britain has more badgers to the square mile than anywhere else in the world.

Polecat (Mustela putorius)

Identifiable by the ‘bandit-mask’ facial markings, the polecat was much persecuted in the past, limiting it by 1915 to a fastness of Wales and the Welsh Borders. In recent decades, it has recolonised much of mainland UK, with numbers reaching 50,000. The animal does not inhabit Ireland or the outer isles. Weighing up to 4½lb, the polecat primarily hunts rabbits and rats, with the pursuit of prey, as with mustelids generally, occurring at night. Frogs are an important item on the spring menu and may be cached for future consumption. The polecat’s preferred habitat is the woodland edge.

Safe to say you would not want to meet a polecat down a dark alley at night. Especially not if you’re a rabbit. European polecat (Mustela putorius). ©Nature Picture Library

Perceived as bloodthirsty pests (‘polecat’ is probably derived from the French poule-chat meaning ‘chicken-cat’, referencing the animal’s penchant for poultry), polecats were declared vermin during the reign of Elizabeth I, with ‘polecat’ used as a term of abuse — notably in Shakespeare’s The Merry Wives of Windsor, with the lines ‘Out of my door, you witch, you rag, you baggage, you poulcat, you runnion!’ In the 1970s, the Labour Party deputy leader Michael Foot infamously compared Thatcherite minister Norman Tebbit to a ‘semi house-trained polecat’. Even by the noisome standards of mustelids, polecat scent is pungent, hence the derogatory Latin name Mustela putorius, meaning ‘foul-smelling musk bearer’.

The average lifespan of the polecat is five years. Pregnancy is direct (no delayed implantation), lasting 40–43 days, with litters of five to 10 born blind and hairless in early summer. Domestic ferrets will hybridise with polecats, the offspring tending to have creamier fur than the true polecat’s dark-brown guard hairs. Territoriality is weaker than in other mustelids, probably because polecats travel to exploit seasonal food sources; ratty farmyards are a favoured winter locale, with the animal denning in haystacks or under sheds. Droppings, which are about 2in–3in long and tar-black, have the typical twisted mustelid appearance.

Pine marten (Martes martes)

The mustelid most likely to be seen in a tree, where it will rest and nest. Indeed, its Irish name is ‘cat crainn’, meaning ‘tree cat’. The size of a small puss, with round ears and a dapper, creamy-yellow cravat (as individual as the human fingerprint), the pine marten was another mustelid afflicted by Victorian anti-predator paranoia. If guilty of stealing hens, it did not wield, as popularly believed, a poisonous claw in its bushy tail to slaughter sheep and then eat the beast nose first.

The tree-hopping pine marten is bad news for grey squirrels, but good news for reds. European pine marten (Martes martes) with caught songbird prey in mouth in forest. (Photo by: Arterra/Universal Images Group via Getty Images)

The majority of the national marten population is to be found in Scotland, with the species’ situation in England and Wales precarious despite reintroductions. Across Europe, the pine marten was widely hunted for fur — in Croatia, marten pelts were used as units of currency in medieval times. Today, the country’s currency is the Kuna, which is also the Croatian word for pine marten.

Although a carnivore, the pine marten has an ecumenical diet, eating both animal and plant material, including small mammals, birds, berries, amphibians, invertebrates, fungi and carrion. They are solitary beasts and highly territorial, so will not abide other adults in their range, which can extend to several thousand acres, vociferously warning off interlopers with growls and hisses. Mating takes place once a year, in July and August, but implantation of the fertilised egg in the uterus is delayed until January to ensure that the two to three kits are born in spring, when food is plentiful.

Contrary to the belief that martens have no natural enemies, they are predated by foxes and eagles. Any lingering ill-feeling towards them must surely be dispelled by developing research suggesting it is the natural-born killer of invasive grey squirrels, to the advantage of homegrown reds. When martens thrive, so does rubicund Tufty.

Eurasian otter (Lutra lutra)

The semi-aquatic otter resembles a galloping, toffee-hued dachshund on land, but is in its element in water, where it is sinuous and gymnastic; the Anglo-Saxons termed our second largest mustelid — males weigh in at 22lb — ‘the water-snake’.

Principally piscivorous, with fish composing 80% of the otter’s diet, Lutra lutra will also take birds, mammals, invertebrates and cold-blooded creatures should opportunity arise. Vibration-sensitive whiskers on the snout and elbow enable the otter to detect prey even in murky water. Soft underfur of 50,000 hairs/cm2 keeps the otter warm and buoyant during extended swimming periods.

A family of otters — referred to as ‘the water snake’ by the Anglo-Saxons — rest on the intertidal seaweed. European river otter (Lutra lutra) Shetland. ©Nature Picture Library

Although otter-hunting dates back to the 14th century, it was always a minor fieldsport in Britain (there were 22 packs registered in 1910) and was dealt an effective death blow by Henry Williamson’s 1927 novel Tarka the Otter, with its telling subtitle clause ‘His Joyful Water-Life’. Dog-headed, with the fun habit of sliding down mud banks, the animal became deucedly difficult to portray as vermin thereafter. Gavin Maxwell’s true-life pet-otter story, Ring of Bright Water (1960), only confirmed Lutra lutra as otterly charming. The otter’s nemeses have been river pollution and habitat loss, not the spear and otterhound. By the 1950s, the British otter was on the edge of extinction, something recognised by the otter-hunting community, which ceased the sport and worked to secure the animal’s future. Improvement in water quality — and thus fish stocks — means that the otter can be seen in every British county today. If you are lucky. Secretive and largely nocturnal, an otter’s territory extends to 12½miles of stream, delineated by droppings (‘spraints’).

Although otters breed at any time, most do so in spring or early summer, with pregnancy lasting two months, after which a litter of two to three cubs is born in the underground natal ‘holt’. The juveniles are able to hunt on their own at around six months, but remain with their mother until they’re around 12-15 months — one theory for the Loch Ness Monster is such a bevy of otters a-swimming.

Weasel (Mustela nivalis)

The belief that weasels suck eggs has lingered for centuries, Shakespeare referencing it in Henry V, when to the unguarded nest of England ‘the weasel Scot comes sneaking, and so sucks her princely eggs’. This is the origin of ‘weasel word’ to refer to any claim that all is fine when the speaker is prevaricating.

Our smallest mustelid — indeed, the world’s smallest carnivore, with females weighing as little as 2oz, hence the alternative name of least weasel — Mustela nivalis is adapted for hunting small rodents in tunnels, especially bank voles and wood mice. Ultra-slim and elongated, weasels can slip through a wedding ring. Despite their miniature stature, they will willingly attack a rabbit. And a chicken.

Weasel (Mustela nivalis) looking out of hole on woodland floor with snowdrops, Sheffield. ©Nature Picture Library

The weasel’s bloodthirsty reputation is aggravated by the habit of excess slaughter. Their fearsome prowess as predators was recognised in classical civilisation, when they were considered omens of death and destruction. According to Greek legend, the weasel was a human bride transformed and, being jealous of other soon-to-be brides, ripped their wedding dresses to shreds. The naturalist Pliny the Elder declared a weasel’s odour sufficiently lethal to kill the monstrous basilisk. Equally outrageous, the medievals thought weasels conceived through the ears and were born by mouth.

The national population of these adaptable, secretive mustelids stands at about half a million — weasels are sexually mature at three months — and is spread across habitats from sea to moor, farmyard to copse. Mortality of the ‘long mouse’, however, is high, with most dying in their first year. Foxes and owls are prime predators. In Britain, the weasel remains chestnut-brown in colour (with white-cream underparts) the year round, but, in mountainous mainland Europe, it may change its pelage to winter-white. Like the stoat’s ‘dance’, the ‘weasel waltz’ is caused by parasitic nematodes placing maddening pressure on the animal’s brain.

Stoat (Mustela erminea)

What’s the difference between a weasel and a stoat? A weasel is weasally recognised and a stoat is stoatally different. Thus the stoat is three times heavier than the weasel, longer at 12in–16in (as opposed to 10in–12in) and sports a distinctive black tip to the tail, together with a bounding gait. Rabbits are staple food, killed by a single bite to the base of the skull; when bunny numbers decline, so does the stoat population. The predilection for rabbits means that stoats frequently inhabit open, grassy ground, hunting along hedges, ditches and drystone walls.

Although it looks similar to the weasel, the stoat is three times heavier, with northern residents able to change their coats in winter. Stoat (Mustela erminea) in white winter coat with fish. ©Nature Picture Library

In northern and upland areas, stoats are turn-coats, going from brown to white in winter to blend with snow; the transformation of pelage is uncommon south of the Humber. The stoat’s winter fur, or ‘ermine’, was considered a symbol of purity (as on display in William Segar’s 1585 portrait of Elizabeth I) — long used for regal robes and the trim on garments of prelates, aristocrats and judges.

Stoats mate in summer, but delay implantation of the fertilised egg until the spring of the following year. They have one litter of six to 12 kits per annum, born in a burrow borrowed from a vanquished rodent or rabbit. Stoats are non-monogamous and litters may have mixed paternity.

Unhappily, the famous, mesmeric ‘whirling Dervish’ dance of the stoat is, rather than a form of rabbit-hypnosis, likely a brain disease caused by a parasitising nematode. In Irish mythology, stoats were believed to hold funeral rites and understand human speech. It was also thought that the killing of a stoat would incur the reprisal of the deceased’s mustelid family spitting in the milk churn to poison it. A stoat met on the road invited bad luck. However, this could be allayed by greeting the creature kindly. If the etymology of ‘stoat’ is uncertain, the suggestion it derives from the Old Dutch for ‘bold’ is entirely apt for this pocket-sized predator.

American mink (Neovison vison)

American mink were first brought to the UK to be bred in fur farms in 1929 — accidental escapes saw the animal breeding in the wild by 1956. The dramatic release of caged mink by animal-rights activists in the following decades likely had little effect on the growing feral population, although the publicity catalysed the Fur Farming (Prohibition) Act 2000.

Dinner’s on ice: the accidentally introduced American mink (Mustela vison) skips away with a frog. ©Nature Picture Library

Lithe, semi-aquatic, efficient and opportunistic, the chocolate-coloured mink proved able to exploit an exceptionally catholic range of prey, from rats to perch — mink being able to remain underwater for 20 seconds — and was complicit in the sharp national decline of the water vole (Arvicola amphibius). Mink have also devastated populations of ground-nesting seabirds in their relentless march across the isles.

As are other mustelids, mink are sexually dimorphic, the male being bigger at 23½in in length, compared with the female’s 17½in. The latter has only one litter a year, the four to six kits born blind and hairless in May and taking meat from five to six weeks of age. Unusually for mammals, ovulation occurs after mating. Dens, invariably pre-established hollows in tree roots or rock formations, are positioned near slow-moving water.

Male mink are solitary, determinedly territorial, marking their fiefdom with rank scat and patrolling it with teeth. Both sexes are mostly nocturnal or active at dusk. Exceptionally, mink may attain 10 years in the wild, although the majority perish before the age of two. They may now be in decline, due to targeting by conservation and game organisations, but also because of the ongoing recovery of the otter, which outcompetes the smaller invader. In continental Europe, there is also a European mink (Mustela lutreola), a somewhat different species and now endangered. The European mink has apparently never existed in Britain.