The sister species of Rüppell's fox is thered fox (Vulpes vulpes). Formitochondrial DNA, Rüppell's fox is nested inside thegenetic lineages of the red fox, calledparaphyly. This may have been caused by a recent divergence of Rüppell's fox from the red fox lineage, or byincomplete lineage sorting, orintrogression of mitochondrial DNA between the two species. Based on fossil record evidence, the last scenario seems most likely, which is further supported by the clear ecological and morphological differences between the two species.[4][5]
Comparison between the skulls of ared fox (left) and a Rüppell's fox (right)
Rüppell's fox is a small fox, measuring 66 to 74 cm (26 to 29 in) in total length, including a tail measuring 27–30 cm (11–12 in) long. There is no pronounced sexual dimorphism, but males appear slightly larger than females. Both sexes are reported to have an average weight of 1.7 kg (3.7 lb).[6] Their coat is sandy with some brown, ticked with numerous white hairs, and fading from reddish along the middle of the back to pure white on the animal's underparts and on the tip of its tail. The flanks are also paler. The head has a more rusty tone on the muzzle and forehead, with dark brown patches on the sides of the muzzle, stretching up towards the eyes. The chin and the sides of the face are white. The whiskers are long, reaching 7 cm (2.8 in).[6]
Its relatively small legs are beige in color, with individual black hairs that turn lighter to white towards the legs. The soles are heavily coated with fur that fully covers the pads, an adaptation to extremes of temperature in the desert,[7] that probably helps to distribute its weight and move easily on sand. The back has a black speckling, resulting in a thick black patch at the base of the tail, which is bushy with a white tip. The fur is very soft and fluffy in two coats, a heavier denser winter coat and a thinner summer coat.[8] The females have three pairs ofmammae.[9]
Similar to other desert-dwelling foxes, Rüppell's fox has large ears to cool it off. Although adults are too large to confuse withfennec foxes, which live in the same area, young Rüppell's foxes can be confused with adults of that species. The larger ears, however, make them easy to distinguish fromred andpale foxes, which also live in some of the same areas. In addition, the coat of a Rüppell's fox is much paler than that of a red fox, while pale foxes lack the white tips on their tails.[6]
It is assumed that the distribution areas have changed historically withdesertification and are mainly limited by competition with thered fox (Vulpes vulpes) and by human settlements.[2] In 2007, an expansion of the occurrence of foxes in theUnited Arab Emirates was documented through the first sighting of the species inAl Dhafra in theEmirate of Abu Dhabi.[10] It seems to avoid the extreme arid regions in the middle of the Sahara, being more abundant on the fringes, in mountain massifs and near oases.[8] Annual rainfall in the region of distribution of the species is normally between 100 and a maximum of 240 mm per year, mostly on the northern edge of the Sahara with a maximum of 150 mm per year.[11]
In Tunisia, the Rüppell's fox occurs in the Saharan habitat inJebil National Park and possibly farther to the south-west.[12]
Rüppell's foxes are monogamous and eithercrepuscular ornocturnal. They usually spend the day resting in their undergrounddens, but in winter they are occasionally active during the day.[11] In Tunisia's Jebil National Park, recent research has shown a prodominently nocturnal activity pattern with very rare crepuscular observations preceding sunrise.[12]
They use two different types of burrows, which are strictly separated: the breeding dens and the resting dens.[6] The resting dens (used outside of the breeding season) are small dens that can hold only one adult fox, and the fox changes dens frequently, on average about every 4.7 days.[13] Breeding dens are larger, and occupied by a pair of adults and their kits. Such dens can sometimes have more than one entrance, although this is unusual.[14] They make a series of short barks during mating and, at other times, can also produce hisses, trills, and sharp whistles. They have been reported to wag their tails, like domestic dogs.[6]
Rüppell's foxes occupy distinctterritories, which they mark with urine, but not with dung as red foxes do. The territories of the members of a mated pair overlap almost completely, but are entirely separate from those of any neighboring pairs. These territories are maintained throughout the year, although the pair occupy separate dens outside of the mating season. The size of the territories varies with the local terrain, but has been reported as around 70 km2 (27 sq mi) inOman, with those of males being larger, on average, than those of females.[14] The foxes range widely during their nocturnal foraging, travelling over 9 km (5.6 mi) in a night.[6]
Rüppell's foxes areomnivores, with a diet that varies considerably depending on what is locally available.[7] In some regions, they are reported to be mainly insectivorous, especially feeding on beetles andorthopterans, while in others, small mammals, lizards, and birds form a larger part of their diet. Plants eaten include grasses and desertsucculents, along with fruits such as dates, and they have also been known to scavenge from humangarbage.[6][14]
Mating occurs in November, a few weeks after the female has prepared her breeding den. Litters up to six kits, although more usually just two or three, are born after agestation period around 52–53 days. The young are born blind.[6] They reach independence at about four months, when they may travel up to 48 km (30 mi) in search of a suitable territory. They can live an average of seven years in the wild, but have been reported to live up to 12 years in captivity.[6]
^abSchinz, H. R. (1825)."Rüppel'scher Hund. Canis Rüppelii". In Cuvier, G.; Schinz, H. R. (eds.).Das Thierreich, eingetheilt nach dem Bau der Thiere als Grundlage ihrer Naturgeschichte und der vergleichenden Anatomie von den Herrn Ritter von Cuvier. Vol. IV. Stuttgart und Tübingen: J.G. Cotta'sche Buchhandlung. pp. 508–509.
^Basuony, A. E.; Saleh, M.; Hailer, F. (2024). "Mitogenomic analysis of Rüppell's fox (Vulpes rueppellii) confirms phylogenetic placement within the Palaearctic clade shared with its sister species, the red fox (Vulpes vulpes)".Mitochondrial DNA Part A.34 (1–8):22–28.doi:10.1080/24701394.2024.2332320.PMID38584459.
^abSheldon, Jennifer W. (1992).Wild dogs: the natural history of the non-domestic Canidae. San Diego: Academic Press. pp. 184–188.ISBN0-12-639375-3.
^abcCuzin, F.; Lenain, D.M. (2004)."Rüppel's fox"(PDF). In Sillero-Zubiri, C.; Hoffmann, M.; Macdonald, D.W. (eds.).Canids: foxes, wolves, jackals, and dogs: status survey and conservation action plan. Gland, Switzerland: IUCN/SSC. pp. 201–205.ISBN2-8317-0786-2. Archived fromthe original(PDF) on 2007-10-12.
^Kingdon, Jonathan (20 November 2014)."Superorder Ferae".Mammals of Africa. Vol. V: Carnivores, Pangolins, Equids and Rhinoceroses. London: A&C Black. pp. 67–69.ISBN978-1-4081-8994-8.
^abSillero-Zubiri, C. (2009). "Rüppel's FoxVulpes rueppellii". In Mittermeier, R. A.; Wilson, D. E. (eds.).Handbook of the mammals of the world. Vol. 1. Carnivores. Barcelona: Lynx Edicions.ISBN978-84-96553-49-1.
^abMeliane, M. K.; Saidi, A.; Boufaroua, M.; Petretto, M.; Riordan, P.; Gilbert, T. (2021). "Rüppell's fox (Vulpes rueppellii) and its habitat in Jbil National Park, Tunisia".African Journal of Ecology.59 (2):535–537.Bibcode:2021AfJEc..59..535M.doi:10.1111/aje.12868.S2CID233562300.
^Nowak, Ronald M. (2005).Walker's carnivores of the world. Baltimore: Johns Hopkins University Press. p. 78.ISBN978-0-8018-8033-9.