The Red fox found in central and southern Europe (from Ireland east to Greece) was described as Vulpes vulpes crucigera in the late 16th Century based on a specimen from Germany. The animal was smaller, with slightly different teeth and a yellower coat than that described three decades earlier from Sweden by Linnaeus. The validity of this subspecies, indeed most subspecies, has been challenged and the current thinking is that the continuity of the Red fox’s range across the Northern Hemisphere makes it unlikely that it’s possible to distinguish many individual subspecies. Indeed, importation of foxes from Europe and movements of foxes within the UK in recent history have probably served to mix and dilute any traits unique to British foxes. Most biologists consequently do not differentiate British foxes from those on the Continent. There are, nonetheless, genetic data from Europe suggesting that some grouping of foxes is warranted but it is unclear how widely this can be applied.
Turning to breeds, early authors suggested that as many as four different ‘types’ of foxes inhabited Britain; from the large, long-legged animals living in the Scottish Highlands, to the small ‘cowardly’ foxes that ‘lurk’ around urban settlements. From these accounts, it certainly seems that a separation of highland and lowland foxes was apparent, although it is unknown whether any such differentiation still exists. Some have suggested that the highland (or ‘greyhound’) fox is descended from Scandinavian foxes, which were imported for sport, and skeleton analysis of museum specimens suggests it is certainly closer in size to those than to central European specimens. That said, it has been argued that other factors, particularly differences in habitat and diet, could equally explain the differences between highland and lowland animals. There is certainly a basic body plan that tends to appear more commonly (although not exclusively) in upland areas; but there are too few data to establish whether these can be considered a breed unto themselves, distinct from the foxes of the lowlands.
Within a species, some populations get separated from their neighbours by landscape obstacles (rivers, seas, mountain ranges etc.) that prevent the two mixing. Consequently, any changes that evolve within the one population and would normally be inherited become restricted within the population. The result is that these genetically isolated populations start to look, and sometimes behave, differently to their neighbours. Carrying this on to its conclusion, they become reproductively isolated and are considered separate species under what we call the Biological Species Concept (see my article on animal taxonomy for more details on this). Before things get that far (and there’s no guarantee they will) there is a period when the two groups look or behave differently but could interbreed to produce viable young, if the opportunity arose; these populations are what we call subspecies.
In essence, therefore, a subspecies is a population of animals that can, based on their appearance, genetics and/or behaviour, be separated from the ‘type’ specimen (i.e. the first one ever described) but could still mix with neighbouring populations were the geographical barrier removed. Some authors have argued that a subspecies is designated purely based on geographical separation, and that it should have nothing to do with how different the two groups look to a human observer. The problem with this stance is that the number of subspecies spirals rapidly out of hand, perhaps unnecessarily. Foxes on the various islands around the UK could qualify as subspecies distinct from those in mainland Britain because they’re separated by a stretch of water. Foxes are, however, accomplished swimmers and what appears to be a water barrier to us may not be to them.
Nowadays we have genetic tests that can give us an indication of how closely related two groups of a species are and this has helped elaborate subspecies classification. The problem for many early naturalists was that they were working solely on anatomy and physiology and this causes controversy over what constitutes a suitable taxonomic feature and, hence, when you drill-down to any grouping below species debate rages. For more information, see: How We Classify Organisms.
A cross to bear
In 1789, German naturalist Johann Matthäus Bechstein described a Red fox caught in the central German state of Thüringen. This specimen was smaller than those typically found in Sweden, from where the Red fox was first described about 30 years earlier, with smaller teeth, more widely space premolars that are seldom, if ever, in contact, and a coat bright yellowish or reddish in colour. This specimen also appears to have had the characteristic dark line running along the length of the back and across the shoulders that makes a ‘cross fox’ (see the colour section of the main Red fox article), because Bechstein named it Vulpes vulpes crucigera (crucigera is Latin for “cross-bearer”). In his 1912 Catalogue of the Mammals of Western Europe, Gerrit Miller recognised this as the subspecies found in central and southern Europe, from Ireland east to Greece. Overall, Miller considered this ‘central subspecies’ to be one of three in Europe; the other two being the ‘northern subspecies’ vulpes (i.e. the one first described by Linnaeus) of the Scandinavian Peninsula and the ‘southern subspecies’ silacea from the Iberian Peninsula.
Not everybody shared Bechstein and Miller’s view that British and central European foxes could be separated from those elsewhere on the continent and, in 1931, in the second volume of his Mammals of Eastern Europe and Northern Asia, Russian zoologist Sergi Ognev argued that tooth size and premolar spacing are both very variable characteristics, concluding that Miller’s data don’t support the assertion that the vulpes subspecies is larger than crucigera. Indeed, in his 1980 opus Red Fox, former Ministry of Agriculture biologist Huw Gwyn Lloyd noted that the terrific variation among European Red foxes makes decisions to lump any together dubious. More recently, Stephen Harris at Bristol University has pointed out that the high levels of dental impaction (teeth packed close together in the skull) among British foxes make it difficult to positively identify them as crucigera.
In a 1995 paper to Annales Zoologici Fennici, Università di Siena biologist Paolo Cavallini used various measurements to compare foxes from various parts of their range. Cavallini found that the animals clustered into three groups: North American foxes; British foxes; and central European foxes. British foxes were more similar to (but still distinct from) European animals than they were to those in North America. Some authors have argued that the difference between Eurasian and North American foxes was a result of their adaptation to the habitat in the 200 years since their introduction from Britain and Europe by early settlers. Cavallini, however, found that the animals from Australia, which were introduced from England and Wales about 160 years ago and now occupy very different habitats to their descendants, were still clearly grouped with their British ancestors by their morphology.
Consequently, Cavallini suggests that the differences in morphology that separate these groups reflects their phylogeny (i.e. how closely related the groups are), rather than the ecological niche they fill. Unfortunately, Cavallini’s dataset was relatively small (comprising only 20 populations), but it certainly implies that a division of British and European animals may be warranted and it would be very interesting to see whether a larger study would yield the same results. Although very common, studying morphology is not the only tool biologists have when it comes to deciding whether populations should be considered subspecies.
Recent genetic work outside of Britain has suggested that some grouping of foxes at the subspecies level may be warranted. In a 1998 paper to the Journal of Zoology, a team of biologists led by Sandro Lovari at the University of Siena in Italy reported on the genetic structure of foxes in the Mediterranean Basin. The biologists analysed special enzymes and DNA from foxes collected from Spain, Italy, Austria, Bulgaria and Israel and found four main groupings: Spanish foxes grouped together; Austrian foxes grouped with those in mainland Italy; Bulgarian foxes were closely allied with those on Sardinia and Sicily (the latter two having been introduced by humans); and Israeli foxes formed a group of their own. Overall, the study found remarkably little inter-mixing of the groups, suggesting that they were “genetically fairly isolated from one another”. Each group would potentially qualify as a subspecies, although the authors don’t propose it.
A similar study on foxes from across Denmark between 1997 and 1999 found that animals from Copenhagen differed significantly, in terms of their enzymes and craniometry (skull measurements), to those in all other regions, suggesting that these urban foxes formed an isolated population, with little gene flow (inter-breeding) with other Danish populations. In this case, the researchers suggest that differences in behaviour between urban and rural foxes may account for this isolation, because geographic separation didn’t appear to be the cause. Finally, a study published in Zoological Science during 2007 reported that foxes from the Japanese islands of Honshu, Shikoku and Kyishu grouped together with those from Europe and East Asia, while those from Japan’s northern island, Hokkaido, were genetically distinct and had their own genetic background; Hokkaido’s foxes are considered to be the subspecies schrencki.
Back in Britain the situation appears to be somewhat different and recent data suggest that our foxes have considerable ‘mixing potential’. In their 2015 paper to the journal Mammal Research, Food and Environmental Research Agency biologist Helen Atterby and her colleagues presented their genetic analysis of 501 foxes collected from around the UK and from two populations in France. Their data show that there’s generally very little structuring in the British fox population, suggesting foxes move around and breed freely.
Using a couple of genetic modelling techniques, they did find support for four broad groups, including foxes living in London and Leicester showing some degree of distinctiveness and foxes from Sussex and Kent clustering with those in Calais in northern France. This latter finding provides genetic support for the reports by early authors such as Henry Dixon and Edward Bovill that foxes were introduced to Britain from the continent, with France being a prominent sourcing site (see QA). Atterby and her co-workers suggest that foxes imported largely to be hunted may not have survived to breed and this may explain why continental genotypes aren’t more widespread in Britain today. The clustering of East Anglian foxes with those in France, coupled with the well-mixed nature of the British population as a whole, also casts doubt on the validity of crucigera as a subspecies unique to Britain.
O ye'll tak' the high fox
In his 1816 A History of the Earth and Animated Nature, poet-turned-naturalist Oliver Goldsmith wrote of how there were three ‘types’ of fox in Britain: the largest, tallest and boldest Greyhound fox that would “attack a full grown sheep”; the small, but strongly built Mastiff fox; and the smaller still and least common Cur fox, which “lurks about hedges and out houses”. Goldsmith’s view was popular among later writers, although not all agreed on the names. John Sherer in his book Rural Life, published in 1860, for example, reckoned Britain was home to the Greyhound, Common and Little Red foxes.
In 1950, Oliver Pike went one further and described four races of fox from Britain: Lowland foxes; the smaller Welsh mountain foxes; small Terriers in northern England and southern Scotland; and Mountain foxes in Scotland. Pike alluded to these types having evolved in response to the harshness of the environment in which they lived and, in his Wild Animals of Britain, he wrote:
“If a fox from an English county was transferred to the wild mountains of Scotland, I doubt very much if he would survive. The Scottish mountain fox is a larger and more powerful animal, and able to attack prey as large and even larger than himself. The long and arduous distances he must travel to find food provides him with powerful and well-formed muscles.”
Many naturalists were slightly more reserved, considering there to be only two types: the Highland (or Greyhound) and Lowland (Common or Terrier) fox. The nineteenth century Scottish naturalist and ornithologist William MacGillivray described the differences between the two types of fox in 1838:
“The largest kind, or that which occurs in the Highland districts, has the fur of a stronger texture and of a greyer tint, there being a greater proportion of whitish hairs on the back and hind-quarters, while two or more inches of the end of the tail are white. The fox of the lower districts is considerably smaller, more slender, of a lighter red, with the tail also white at the end. … The skull of the Highland fox appears remarkably large and strong beside that of the ordinary kind, and the breadth is much greater in proportion.”
In his 1904 Mammals of Great Britain and Ireland, John Guille Millais agreed with the separation of lowland and highland foxes, although he placed a greater emphasis on colouration, writing:
“It may, however, be taken as a broad rule that the large dark and grey forms are found inhabiting the mountains, whilst the smaller red and pale types frequent the valleys and plains.”
In 1941, the late Bristol Museum zoologist H. Tetley published a short paper to the Proceedings of the Zoological Society of London in which he looked at museum collections of Red foxes and compared those from Scotland with those from central Europe, based on skull dimensions, skeleton size, teeth arrangement, coat colour etc. Tetley concluded that Scottish foxes were considerably larger than those from central Europe; their measurements more closely matched animals from Scandinavia. Tetley explained:
“On the whole, therefore, I cannot see that there is any distinction between the Scandinavian and the Scottish Fox as represented by specimens from the Scottish Highlands, and I consider that both are Vulpes v. vulpes.”
L. Harrison Matthews, in his 1952 British Mammals, agreed with Tetley in separating the highland and lowland foxes, and a study comparing 87 English and Scottish foxes that was published in 1956 by Ivan Hattingh also supported Tetley’s findings, concluding that the Scottish fox was a distinct race, although he failed to find any significant differences between highland (Westmorland) and lowland foxes in England. In his 1968 book Wild Fox, Roger Burrows also agreed, arguing that—based on body and skull measurements—the Scottish fox is conspecific with (the same species as) the Scandinavian fox. Thus, these authors considered the Scottish fox to be Vulpes vulpes vulpes and the English fox Vulpes vulpes crucigera.
These studies haven’t, unfortunately, laid the matter to rest for many naturalists, because there are many early hunting reports from highland areas of England (e.g. the Cumbrian Fells) that clearly describe ‘long legged’ Greyhound foxes leading hounds on exceptionally long runs, seeming to have almost endless stamina compared with their smaller, shorter legged lowland cousins. Of course, many examples of very long chases (three days being the longest I’ve come across!) probably involve several foxes; a weary fox running into undergrowth and ‘putting up’ one resting there. In his Town Fox, Country Fox, Brian Vezey-Fitzgerald points out that:
“Hounds will always follow the fresher line. And you can always tell when they change to a fresher line by the change in their cry.”
Vezey-Fitzgerald suggests that the hunted fox may ‘know’ where neighbouring foxes tend to lie up and may head for that location in order to shake its pursuers. There is, to my knowledge, no proof of this, but it doesn’t seem entirely unreasonable and (deliberate or not) it would certainly explain some of the exceptional runs described by hunters. This doesn’t, however, explain the morphological differences the hunters describe.
Dilution of the British red fox?
My friend and native ‘Lakelander’ Ron Black researched highland fell foxes in some detail and has suggested to me that, if one unites Scottish and English highland foxes, the Greyhound fox may have been the ‘original British fox’, until animals from the continent were imported during the mid-19th Century for sport. Sadly, Ron passed away in September 2017 following a battle with cancer and his attempts to understand the genetics of fell foxes remains unfinished.
Foxes were certainly imported to Britain from Europe and translocated within Britain, particularly as numbers declined following heavy persecution and severe outbreaks of sarcoptic mange. Indeed, Vezey-Fitzgerald notes that foxes were imported from continental Europe during the mid-1800s and released into the countryside at a rate of more than one thousand per year and animals were translocated from other parts of Britain to Somerset and Devon as late as the 1920s following a serious mange epidemic (see QA). Similarly, in his excellent book Running with the Fox, Oxford University zoologist David Macdonald wrote:
“Where [fox] numbers ran short foxes were bought and released (such ‘bagged’ foxes sold for 10 shillings at the Leadenhall Market [in London] in 1845) and included a brisk trade in imports from the Continent.”
Based on the descriptions of early Cumbrian hunters it seems almost without doubt that the foxes they hunted were larger and faster than those we see across most of Britain today. Unfortunately, there is little evidence to suggest that these animals still survive in the Fells. Certainly, I know of no empirical evidence to support such a separation today, although there are data from the USA suggesting a separation by altitude of native vs. introduced foxes, so a similar situation in Britain cannot be dismissed out of hand.
To my mind, it seems possible that the foxes which originally recolonised Britain following the retreat of the ice sheets at the end of the last Ice Age probably spread widely throughout the country. Those inhabiting highland regions could subsequently have evolved to suit the terrain, with a larger body size and longer legs offering advantages (reduced heat loss, lower metabolic rate, ability to take larger prey etc.) in cold, wet and snowy environments. Those in lowland regions, however, probably remained close in appearance to their European ancestors. Any unique traits evolved by British lowland foxes could easily be diluted by interbreeding with imported animals.
Adaptation of highland and lowland forms could have reached the point where the lowlanders were simply unable to compete effectively with the highlanders for high altitude habitats, while the highlanders were easily out-competed at lower altitudes by the lowlanders – the result being a separation, ultimately genetic isolation, of the populations. This is, of course, speculative and, while it works in theory, it remains to be supported by any genetic evidence. (For a detailed summary of the hill hunting literature pertaining to Greyhound foxes, the reader is directed to Ron Black’s article The Lost Foxes of Lakeland – and other places besides).
The question of whether subspecies or breeds of foxes exist in Britain may never be fully resolved, but most recent authors have adopted the view of Gordon Corbet who, in his 1978 book The Mammals of the Palaearctic Region, concluded that the continuity of the Red fox’s range is so great that it’s doubtful any discrete subspecies can be recognised. There are some genetic data from foxes in the Mediterranean that suggest distinct groups can be made and that there may be a case for assigning some subspecies, but the data simply don’t exist for a sufficiently large geographical area to be certain whether similar groupings can be applied to other Eurasian populations. Consequently, the majority of biologists now consider that Vulpes vulpes is just a highly variable species that ranges throughout Europe and Asia and do not attempt to categorize it further.