Small British Mammals: Moles

If hedgehogs are generally welcome in suburban gardens, there's one native British animal that generally isn't, and, like the hedgehog (and shrews) it belongs to a group of insect-eating mammals technically called the Euliptophyla. This, of course, is the European mole (Talpa europaea), sometimes called the "common mole" if we even need to distinguish it from other kinds of mole at all.

As the name implies, European moles are essentially unique to Europe. They are found throughout much of the continent, from northern Spain, Italy, and the central Balkans in the south to southern Sweden and Finland in the north. They are not found in southern Russia, but do reach just beyond the boundary with Asia in the northeast. While they are not native to Ireland, they are found on a number of smaller islands off the coasts of England, Scotland, and Denmark.

Small British Mammals: Hedgehogs

There can be few British mammals more distinctive and well-loved than the hedgehog. Indeed, a 2016 poll found that it is, by a substantial margin, Britain's favourite mammal. (For what it's worth, and by a similar margin, the robin is apparently our favourite bird).

The animal that Brits simply call "the hedgehog" is more accurately the European hedgehog (Erinaceus europaeus), and it's found through pretty much the entirety of western Europe. In fact, across much of the continent, the eastern border of its occurrence is very roughly where the old Iron Curtain used to be. That's a simplification, of course, and aside from some border regions of former 'Eastern Bloc' countries, they are also found quite extensively in the Czech Republic, Estonia and parts of north-west Russia. They are also common on several larger islands, including Ireland, Corsica, Sardinia, and Sicily, and, in more recent times, they have been introduced to the Azores.

Small British Mammals: Water Shrews

Two of the three species of shrew found in Britain are very similar to one another in appearance and habits. This is hardly surprising, given how closely related they are. The odd one out, however, is not quite such a close relative, and is rather more distinctive.

This is the Eurasian water shrew (Neomys fodiens), which unsurprisingly, is simply called the "water shrew" in Britain. Despite its differences, even at first glance, it's pretty obvious that it is a shrew: it's a small, long-tailed animal with short fur, tiny ears, small eyes, and a narrow, pointed, snout filled with sharp teeth. However, by the standards of shrews, it's unusually large. Fully grown adults can reach as much as 10cm (4 inches) in length, and weigh up to 25g (0.9 oz.), closer in size to a typical mouse than to other native shrews.

The Smallest British Mammals: Shrews

Common shrew

For some reason that I no longer recall, a picture of a shrew cropped up while I was talking with a friend on the internet. "That's a mouse," she insisted. "No," I said, "it's a shrew." "Mouse!"

It was only later that I remembered that the German word for "shrew" is spitzmaus (literally "sharp/pointed mouse") and, since my friend was Austrian, she wasn't necessarily entirely wrong. From a certain perspective, perhaps to German-speakers, all these small, furry, long-tailed things are mäusen.

And it's certainly true that shrews do look, superficially, quite like mice. They tend to be smaller, with narrower snouts, and very small ears and eyes, but there is something quite mouse-like about them. Nonetheless, shrews (unlike, say, voles) are not rodents. In fact, as placental mammals go, they aren't even particularly related to rodents - humans are more closely related to mice than shrews are.

Small British Mammals: Hares

Brown hare

The most visited post on this blog remains that explaining why rabbits are not rodents (their incisor teeth may look like those of rodents, but there are differences, and they have an extra set). I've also discussed, briefly, how rabbits manage to digest tough plant matter without the extra stomach chambers found in cows and similar animals by using the large bowel as a second stomach, and then eating the food twice.

All of these things are, of course, also true of the close relatives of rabbits, hares. There are two species of hare living wild in Britain, of which the more common is the European or brown hare (Lepus europaeus).  Like rabbits, they were only introduced to Britain during, or perhaps slightly before, Roman times, but they are now widespread across England, Wales, and Scotland.

Small British Mammals: Rabbiting About Rabbits

Over the course of the last two thousand years, a number of native British mammals have been driven to extinction. These were mostly the larger ones that were considered either dangerous (wolves) or tasty (wild boar). But we have also managed to introduce a few, mostly smaller, animals that were not originally native to the islands but are now widespread. The grey squirrel, being relatively recent, is probably the best known of these, although the brown (or "sewer") rat is another, only arriving in the 16th century.

Another example was first introduced in Roman times, and so has been here rather longer - but, still, it could be argued that it's not technically native. This is the rabbit (Oryctolagus cuniculus).

Small(ish) British Mammals: Beavers

There are, arguably, a couple of reasons why beavers don't really belong in this series on the small native animals of Britain. So far, I have looked at mice, voles, rats, and squirrels, all of which are undeniably both small and British... but they are also all rodents, and so I may as well complete the set of such animals by including the one that isn't really all that small.

Indeed, weighing in at around 15 to 20 kg (33 to 44 lbs) on average, and occasionally a fair bit larger, the Eurasian beaver (Castor fiber) ties with its American cousin for the honour of being the second-largest living rodent, after the capybara. It is also, of course, a very distinctive animal, and one whose general appearance most people are surely familiar with.

Small British Mammals: Squirrels

Red squirrel

The majority of rodent species look, more or less, like mice or rats, depending on their size. But there are a number of exceptions among the many, many, kinds of rodent in the world. Probably the best known such exceptions in Britain are the squirrels.

By far the most common tree squirrel in Europe, and perhaps the most widespread species of squirrel anywhere in the world, is the red squirrel (Sciurus vulgaris), sometimes called the "Eurasian red squirrel" to distinguish it from the North American animal of the same name. This lives almost everywhere in Europe, apart from the Mediterranean islands, southern Greece, and Portugal, and is one of a relatively small number of native wild mammals in Ireland. Further east, they inhabit just about every temperate, forested, region of Asia, reaching as far as Korea, northern Japan, and the coast of the Bering Sea.

About twenty different subspecies are currently recognised, but there seem to be few reliable ways of distinguishing between them. For instance, while most red squirrels are, in fact, red, a significant proportion are darker, or even near-black. These are apparently more common in the dense highland forests of the Alps and the Altai Mountains, but are not a reliable indicator of subspecies, since they are found in other populations, too.

Small British Mammals: Dormice

Hazel dormouse

The general body plan of looking like a mouse or rat is one that's proven very successful for rodents; a huge number of rodent species, not all of which are closely related, broadly fit this description. Both the mouse family and the "hamster family" (which includes deer mice, pack rats, and voles, among others) are considered to be part of a larger grouping of related rodent families called the Myomorpha. This roughly translates as "mouse-like rodents" and it's a group that includes, under the most common current system, seven different families.

Historically, the Myomorpha was defined based on the structure of the jaw muscles, so that it included some animals, such as jerboas, that don't necessarily look all that much like regular mice. But modern genetic analysis has shown that this anatomic feature isn't as unique as we'd thought, and seems to have evolved at least twice, perhaps in response to a similar dietary requirement in the two different groups. As it happens, the jerboas got to stay in the "mouse-like" group (if only just), but one family of animals that manifestly do look like mice turned out to be something else entirely, and about as unrelated to true mice as it's actually possible to be among living rodent species.

Small British Mammals: Bank Voles

I had intended to wrap up voles a couple of weeks ago, but it turned out that there was so much to say about water voles in particular that it made more sense to add in an extra post to cover everything else. So, here we are with the fourth and final species of vole found in Britain: the bank vole (Myodes glareolus).

Although water voles are more closely related to common voles and their kin than the bank voles, it is the latter that have the closest physical resemblance. While most voles are broadly similar in shape, bank voles are also roughly the same size as the common and field voles, and can be distinguished (without close examination of the skeleton) by the fact that the fur on their backs typically has a distinct reddish tinge. A few instances of individuals with other colours have been noted - including a pure white one that had somehow survived to adulthood without being eaten - but these are rare.

Small British Mammals: Ratty and the Water Voles

Four different species of vole live wild in Britain, with, perhaps, the field vole being the one that is most typical of the wider group. However, it's perhaps a different species that has the most claim to fame, appearing as one of the central characters (confusingly named "Ratty") in the popular children's book The Wind in the Willows.

Ratty is a water vole (Arvicola amphibius), an animal with a number of differences from common and field voles, despite being fairly closely related to them. Before discussing the species in more detail, we should acknowledge that, over the years, there has been considerable confusion as to what the scientific name of this animal actually is - and, for once there's quite a good reason for it.

Small British Mammals: Common and Field Voles

Field vole

In many respects, voles are extremely similar to mice. In many languages, the local word for 'mouse' also describes voles, and this was even the case in English prior to around the 19th century, when the term "vole-mouse" was borrowed from a now-extinct Scandinavian tongue, and shortly thereafter abbreviated to simply "vole". In its original language, it literally meant "field", and a similar etymology can be seen in languages such as German (Feldmaus) and French (campagnol) among many others.

Scientifically, voles have also been mixed in with the mice at different times. While they have recognised as a distinct group with their own scientific name since 1821, for much of the 20th century they were considered a subgroup within the wider mouse family. That's really only changed in the last 20 years or so, as genetic and biochemical evidence has shown that the two groups, while related, have distinct evolutionary histories.

Small British Mammals: Rats!

Brown rat

The term "rat", as commonly used, has no defined biological meaning. A "rat" is simply any rodent that looks at least somewhat like a mouse, but is larger. Animals fitting this description have evolved multiple times, so that rats do not form a single evolutionary group, and not all of them are even members of the mouse family.

Nonetheless, there is a biological group that we can call, for lack of a better term, the "true rats" (technically the "Rattini") which includes the animals that most people likely think of when the term "rat" is used without further qualification. There are two species of this kind of animal in Britain, not least because both of them are found just about everywhere else as well.

Small British Mammals: The Smallest Mice

The smallest species of mouse native to Britain, and, indeed, one of the smallest species of mice anywhere in the world, is the harvest mouse (Micromys minutus). With a typical adult weight of around 7 grams (0.25 oz.) or so, it's only around a quarter of the weight of a typical house mouse, and is known by terms translating as "dwarf mouse" in a number of European languages, including both German and Greek.

Harvest mice are widespread, being found across much of Europe, and in a band across Asia that reaches as far as Japan and Taiwan in the east. A 2009 study from Vietnam suggested that the harvest mice there might be a separate species, but it was small scale and not yet fully accepted. Certainly, it's an unusually hot climate for harvest mice which, in Europe, are found only in northern Spain and Italy, only sporadically in Greece, and not in Portugal at all. On the other hand, while they are reasonably common in central and southern Finland and southern Scotland, they are rare in Sweden and absent from Norway. (They also don't reach Ireland, but the sea is the likely barrier there, rather than the climate).

Small British Mammals: Field Mice

Wood mouse

While the common house mouse is likely one of the most familiar of all animals living wild in Britain, it is only one of four species of mouse native to the islands. (France and Germany, for comparison, have six each, although they aren't the same six). Of the other three, the closest relatives of the house mouse are the two species of field mouse, which are also found widely on continental Europe.

Field mice have benefited less from the presence of humans than house mice, since they tend to avoid human dwellings, and there are rather a lot of those in Europe. Given their common name, however, one might suppose that they have at least benefited from the spread of agricultural land. This, however, only true of one of the British species. This is the wood mouse (Apodemus sylvaticus), sometimes also known as the "long-tailed field mouse". In Britain, when the term "field mouse" is used without qualification, it typically means this one.

Small British Mammals: House Mice

Over the last few years, I have done a roughly annual series covering particular groups of mammals, exploring all the different species, familiar and unfamiliar, that belong to them. (If you haven't read the past ones, the link "Synapsida Series" points to the list of them; note that the individual posts appear in reverse chronological order once you select a series to view). One problem with selecting which groups to cover in a given year is that only some groups will really work, and, even then, some are clearly better than others.

One problem, for example, is that some groups are simply too large, and if you split them down into narrower groups that are more easily handled, there's no longer enough variety for it to be worth it. Such is particularly true of small mammals. There are over 700 species in the mouse family, for instance, with over 500 of those in the "murine" subfamily, which includes all of the familiar ones. Even if it would be practical to describe them all, most of the individual species haven't been studied in any detail, so you'd rapidly get a long list of "looks mouse-like, lives in XX".