Interactions

The many interactions that a red fox has can be separated into a couple different categories. These categories include competition, predation, parasitism, interspecies interactions and human interactions.

Interspecies Interaction

Interspecies interaction (interaction between red foxes) is the most common interaction. The basic social unit is a pair, but groups of up to six members may share a territory, depending on habitat. In these groups there is exclusively one adult male and 2-5 vixens (generally related). Red foxes communicate with each other through facial expressions, vocalizations and scent marking. Some 28 different categories of vocalization have been described and are used to communicate over long distances and at close quarters. Each individual red fox has a characteristically different voice. Scent markings involve urine and feces, anal sac secretions, violet or supracaudal glands as well as glands around the lips, in the angle of the jaw and between pads of the feet (Sillero-Zubiri et al. 2004). Another common interspecies interaction is raiding the food stashes of neighboring foxes. Ironically enough, this interaction is a mutual benefit as a whole, for in the long run, fewer of the hidden stashes are forgotten and lost forever, thereby increasing the overall food supply. Any minor losses a fox experiences are generally recovered by raiding the stashes of neighboring foxes (Liska 2013). To learn more about caching, look at adaptations. The result of interactions between red foxes can be seen on a larger scale by analyzing territory. Shifting territories in the city display a unique system of interaction. While territories in the suburbs were spatially stable, those in the city drifted in location continually, but they did so in a way such that the juxtaposition of neighboring groups remained essentially unaltered across generations of occupants (C.P. Doncaster and D.W. MacDonald 1991).

Predation

Foxes interact with a large number of species as predators. Being such a widespread candid, diet varies from habitat to habitat, allowing for a multitude of predatory interactions across the globe. Red foxes are adaptable and opportunistic omnivores, with a diet ranging between invertebrates, mammals, birds and fruit. Foxes typically kill birds and mammals up to about 3.5 kg (7.7 lbs). Their diet changes seasonally from mostly animal matter in the winter to insects and fruit in the summer and fall. During seasons of abundance, blueberries (Vaccinium spp.), raspberries (Rubus spp.) and black cherries (Prunus serotina) may constitute almost 100 percent of the diet. Red Foxes may disperse seeds by eating these fruits which would make this relationship mutualistic (Encyclopedia of life 2013).

                             Competition

Red foxes compete with many other organisms for resources and territory. A unique form of competition occurs when red foxes enlarge the burrows of other species such as rabbits, marmots, European badgers and other foxes, to save themselves the trouble of digging their own dens. Red foxes compete with Artic foxes where the two species exist sympatrically in the Eurasian tundra. Red foxes are larger and generally are known to out-compete Artic foxes, sometimes known to kill both adults and young. Red foxes are limited to the north of their range and in that respect the Artic foxes are better adapted to the limited food supply and the colder conditions. Grey wolves and red foxes are in some cases sympatric throughout their shared range, however due to little dietary overlap there is little competition between them. Such is not the case with coyotes, who share a similar diet. This is an example of inference competition, the coyote tends to be distributed in areas where there are sufficient resources and the red fox will inhabit the adjacent areas with lower food resources. Red fox numbers tend to be greater when coyotes are absent and they do not rear cubs when coyotes are active. In habitats where red and gray foxes coexist, exploitative competition for food is likely and habitat partitioning is common. Red and gray foxes are similar in size and as a result territory is partitioned between the species. Red foxes are known to kill kit foxes and stone martens in areas where they feed on similar resources. Gray foxes, though smaller, dominate red foxes in areas of eastern North America (Sillero-Zubiri et al. 2004).

Foxes as Prey

Red foxes have few natural predators in comparison to the numerous organisms which they prey on. Some of the organisms which have been known to kill the red fox include golden eagles, badgers, domestic dogs, Eurasian lynx, coyotes and wolves. Badgers and domestic dogs are known to kill only the cubs (Sillero-Zubiri et al. 2004). Follow this link to watch a video of a golden eagle taking down a fox.

Interactions with Humans

 Humans contribute to a large percentage of the predation experienced by red foxes on the basis that they are considered to be pests to many (see Interesting). In the UK, people attempt to control populations through secondary poisoning, shooting and other methods making humans the leading cause of fox mortality (Heydon and Reynolds 2000). In addition to control, foxes are also hunted with dogs, not only in the UK, but also France, Belgium, Portugal, Italy, Germany, Switzerland, Australia, the US and Canada. In the UK, these hunts account for the deaths of 21,500-25,000 foxes annually. Hunting red foxes is not just a modern sport however, for they have been hunted since the 4th century B.C. These statistics are separate from those regarding hunting and trapping for fur. Between 1985 and 1986 worldwide trade of wild-caught foxes was 1,543,995 pelts worth 50 million dollars (Macdonald et al. 2000). Their value for fur has made raising foxes for fur economically profitable. Not all human-fox interactions result in the death of the fox however, a study done in Russia has resulted in tamed foxes (see more in Interesting). After many generations of selective breeding, the red fox can be bought as a much calmer domesticate of its wild counterpart.

Parasites and Disease

The red fox is host to a wide range of parasites including at least 58 species of helminths in Europe alone. One of the most serious and devastating parasites infecting foxes is the skin-dwelling mite (Sarcoptes scabei var vulpes) which causes a condition known as sarcoptic mange. Sarcoptic mange appeared in Finland in 1967 and spread to Norway and Sweden in the 1970s and 1980s where it reduced the red fox population by over 70%. Next, it spread across most of England including Bristol, UK where it wiped out over 90% of the fox population. Other locations where sarcoptic mange has spread are Spain and New York. Considering how solitary red foxes are, to have a disease wipe out such a large proportion of the population is incredible. When comparing sarcoptic mange to the Black Death in Europe, we can note that the Black Death killed 30% of the population in areas where overcrowding made the spreading of disease incredibly easy, on the other hand red foxes, which characteristically are solitary organisms experienced a population reduction of over 70% (Sillero-Zubiri et al. 2004). I would feel safe in suggesting that sarcoptic mange could be considered the red fox’s plague.

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The red fox, due to its wide geographic range has numerous interactions, perhaps far more than studied. The interactions above are not and cannot be considered complete on this basis. Interactions vary based on region and habitat.

              

Are you ready to take a break from the science and look at some purely entertaining information? If so, go to the Interesting section.

To give credit, where credit is due, go to References!

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Visit MultipleOrganisms.net for more great interactions!