Thebat-eared fox (Otocyon megalotis) is a species offox found on the Africansavanna. It is the only extant species of the genusOtocyon and abasal species ofcanid. Fossil records indicate this canid first appeared during themiddle Pleistocene. There are two separate populations of the bat-eared fox, each of which makes up a subspecies. The bat referred to in its colloquial name is possibly theEgyptian slit-faced bat (Nycteris thebaica), which is abundant in the region and has very large ears. Other vernacular names include big-eared fox, black-eared fox, long-eared fox, Delalande's fox, cape fox, and motlosi.
It is named for its large ears, which have a role inthermoregulation. It is a small canid, being of comparable size to the closely relatedcape fox andcommon raccoon dog. Its fur varies in color depending on the subspecies, but is generally tan-colored and hasguard hairs of a greyagouti color. The bat-eared fox is found inSouthern andEast Africa, though the two subspecies are separated by an unpopulated region spanning approximately 1,000 km (620 mi). In its range, the bat-eared fox digs dens for shelter and to raise its young, and lives in social groups or pairs that hunt andgroom together.
The bat-eared fox eats mainlyinsects—a diet unique among canids. It forages in arid and semi-arid environments, preferring regions with bare ground and whereungulates keep grasses short, and locates prey by using its hearing, walking slowly with its nose to the ground and ears tilted forwards. Most of its diet is made up ofharvester termites, which also hydrates the bat-eared fox, as it does not drink from free-standing water. By feeding on harvester termites, it acts as a means of population control for these insects, which are considered pests in regions populated by humans. In such regions, it has been hunted for its fur. No major threats to the bat-eared fox exist, and as such it is considered to be aleast-concern species.
The bat-eared fox'sgeneric nameOtocyon is derived from theGreek wordsotus (οὖς) for ear andcyon (κύων) fordog, while thespecific namemegalotis comes from the Greek wordsmegas (μέγας) for large andotus (οὖς) for ear.[4] Thecommon name for the bat-eared fox is likely taken from theEgyptian slit-faced bat (Nycteris thebaica), due to the bat's similarly large ears and abundance in the bat-eared fox's geographic range.[5] Other vernacular (common) names for the bat-eared fox include big-eared fox, black-eared fox, long-eared fox,[6] Delalande's fox, cape fox,[a] and motlosi.[4]
The bat-eared fox is the only living species of thegenusOtocyon.[1] Itsscientific name, given byAnselme Gaëtan Desmarest, was initiallyCanis megalotis (due to its close resemblance to jackals), and later changed bySalomon Müller which placed it in its own genus,Otocyon; its large ears and differentdental formula warrant inclusion in a genus distinct from bothCanis and true foxes (Vulpes).[5]
Due to its unusualdentition—3.1.4.3-43.1.4.4-5 × 2 = 46-50, the largest number of teeth known in any non-marsupial land mammal—the bat-eared fox was previously placed in a distinctsubfamily ofcanids, Otocyoninae, as no relationship to any living species of canid could be established.[7]
Otocyon megalotis is regarded as having affinities with the vulpine line,[7] andOtocyon was placed with high confidence as sister to theclade containing both theraccoon dog (Nyctereutes) andtrue foxes (Vulpes), occupying abasal (closest to the base) position withinCanidae.[8][9]
The followingcladogram is based on figures by Lindblad-Toh et al., 2005:[10]
Otocyon is poorly represented in the fossil record. It is suggested the genus forms a clade withPrototocyon, an extinct genus of canid.[11][12] In theOlduvai Gorge,Tanzania, fossils of the related extinct fox species first consideredOtocyon recki have been found that date back to the late Pliocene or early Pleistocene.[4]O. recki is now often placed inPrototocyon;[13][14] fossil records specifically ofOtocyon megalotis have been identified in sediments only as old as themiddle Pleistocene.[15] These fossils, known from the Lainyamok locality of Kenya, date back0.3 million years.[2]
Bat-eared foxes range in weight from 3 to 5.3 kg (6.6 to 11.7 lb). Their head and body length is 46–66 cm (18–26 in), tail length is 23–34 cm (9.1–13 in), shoulder height is 30–40 cm (12–16 in),[16] and the notably large ears are 11–13 cm (4.3–5.1 in) long.[17] The species displays a degree ofsexual dimorphism, in that females are generally larger and heavier than males.[18]
Generally, thepelage is tan-colored, with grayguard hairs of anagouti coloration.[16] The undersides and throat are pale. The limbs are dark, shading to dark brown or black at their extremities. The muzzle, the tip and upperside of the tail and the facial mask are black. The insides of the ears are white.[4] Individuals of the East African subspecies,O. m. virgatus, tend toward abuff pelage with dark brown markings, as opposed to the black ofO. m. megalotis. The proportionally large ears of bat-eared foxes, a characteristic shared by many other inhabitants of hot, arid climates, such as thedesert cottontail,[19] help todistribute heat. They also help in locating prey.[17]
The teeth of the bat-eared fox are much smaller those of other canid species,[18] excepting thebush dog (Spetothos venaticus) anddhole (Cuon alpinus).[20] Themolars are much more blunted and theroots are stronger than those of other canids, and the teeth have lessshearing capability. These are adaptations to itsinsectivorous diet and avoidance of soft foods.[18] The bat-eared fox possesses 4-5 lowermolar teeth and 3-4 upper molars, a number notable as it is greater than the number of lower or upper molars possessed by any other extanteutherian[b] or canid, respectively.[7]
The teeth are not the bat-eared fox's onlymorphological adaptation for its diet. On the lower jaw, a step-like protrusion is present called the subangular process, which is present in only a few canid species and both increases the bite force of themasseter muscle[21] and anchors the largedigastric muscle to allow for rapid chewing. Thedigastric muscle is also modified to allow for opening and closing the jaw five times per second.[4]
The bat-eared fox has adisjunct distribution across the arid and semi-arid regions of Eastern and Southern Africa, in twoallopatric populations (representing each of the recognizedsubspecies) separated by approximately 1,000 km (620 mi). SubspeciesO. m. virgatus extends from southernSudan,Ethiopia andSomalia, throughUganda andKenya to southwesternTanzania;O. m. megalotis occurs in the southern part of Africa, ranging fromAngola throughNamibia andBotswana toSouth Africa, and extends as far east asMozambique andZimbabwe,[3] spreading into theCape Peninsula and towardCape Agulhas. Home ranges vary in size from 0.3 to 3.5 km2 (0.12 to 1.35 sq mi).[4] The two disjunct ranges ofO. megalotis were likely connected to each other during thePleistocene epoch.[22]
Bat-eared foxes are adapted to arid or semi-arid environments. They are commonly found in shortgrasslands, as well as the more arid regions of thesavannas, along woodland edges, and in openacacia woodlands.[17][20] They prefer bare ground and areas where grass is kept short by grazingungulates[4] and tend to hunt in these short grass and low shrub habitats. However, they do venture into areas with tall grasses and thick shrubs to hide when threatened.[23]
In addition to raising their young in dens, bat-eared foxes use self-dug dens for shelter from extreme temperatures and winds. They also lie under acacia trees in South Africa to seek shade during the day.[4]
Bat-eared foxes are social animals. They live in pairs or groups, depending on the subspecies. In southern Africa (ssp.megalotis), bat-eared foxes live inmonogamous pairs with pups, while those in eastern Africa (ssp.virgatus) may live in pairs, or in stable family groups consisting of a male and up to three closely related females with pups.[24][20] Individuals forage, play, and rest together in a group, which helps in protection againstpredators. They engage in frequent and extendedallogrooming sessions, which serve to strengthengroup cohesion, mostly between mature adults, but also between young adults and mature adults.[4]
Threat display of bat-eared fox
Visual displays are important in communication among bat-eared foxes. When they are looking intently at something, the head is held high, eyes are open, ears are erect and facing forward, and the mouth is closed. When an individual is in threat or showing submission, the ears are pulled back and lying against the head and the head is low. The tail also plays a role in communication. When an individual is asserting dominance or aggression, feeling threatened, playing, or being sexually aroused, the tail is arched in an inverted U shape. Individuals can also usepiloerection, which occurs when individual hairs are standing straight, to make it appear larger when faced with extreme threat. When running, chasing, or fleeing, the tail is straight and horizontal. The bat-eared fox can recognize individuals up to 30 m (98 ft) away. The recognition process has three steps: First they ignore the individual, then they stare intently, and finally they either approach or attack without displays. When greeting another, the approaching individual shows symbolic submission which is received by the other individual with a high head and tail down. Few vocalizations are used for communication, but contact calls and warning calls are used, mostly during the winter.Glandular secretions and scratching, other than for digging, are absent in communication,[4] although they appear to establishpair bonds byscent marking.[25]
In the more northern areas of its range (aroundSerengeti), they arenocturnal 85% of the time. However, around South Africa, they are nocturnal only in the summer and diurnal during the winter.[26]
Bat-eared foxes require water forlactation,[30] but have not been observed drinking from free-standing water.[4] They meet their water requirements through the high water content of their diet.[30]
Bat-eared foxes usually hunt in groups, often splitting up in pairs, with separated subgroups moving through the same general area.[31] When termites are plentiful, feeding aggregations of up to 15 individuals from different families occur.[32] Individualsforage alone after family groups break in June or July and during the months after pups birth.[4]
Prey is located primarily by auditory means, rather than by smell or sight.[31] Foraging patterns vary between seasons and populations, and coincide with termite availability. In eastern Africa, nocturnal foraging is the rule, while in southern Africa, nocturnal foraging during summer slowly changes to an almost solelydiurnal pattern during the winter. Foraging techniques depend on prey type, but food is often located by walking slowly, nose close to the ground and ears tilted forward.[7] It usually occurs in patches, which match the clumped prey resources, such as termite colonies, that also occur in patches. Groups are able to forage on clumps of prey in patches because they do not fight each other for food due to their degree of sociality and lack of territoriality.[23] As the bat-eared fox's range overlaps with that of theaardvark, it will take advantage of termite mounds opened up by the latter animal, as willaardwolves.[33]
Juvenile bat-eared foxes playing outside of their den in Naboisho Conservancy,Kenya, just outside ofMaasai Mara National Reserve
The bat-eared fox is predominantly sociallymonogamous,[34] although it has been observed inpolygynous groups.[20] In contrast to other canids, the bat-eared fox has a reversal in parental roles, with the male taking on the majority of the parental care behavior.Gestation lasts for 60–70 days and females give birth to litters consisting of one to six pups. Beyondlactation, which lasts 14 to 15 weeks,[4] males take over grooming, defending, huddling, chaperoning, and carrying the young between den sites. Additionally, male care andden attendance rates have been shown to have a direct correlation with pup survival rates.[35] The female forages for food, which she uses to maintain milk production, on which the pups heavily depend. Food foraged by the female is not brought back to the pups orregurgitated to feed the pups.[4]
Pups in theKalahari region are born September–November and those in theBotswana region are born October–December. Young bat-eared foxes disperse and leave their family groups at 5–6 months old and reach sexual maturity at 8–9 months.[4] Bat-eared foxes have been recorded reaching maximum lifespans of over 14 to 17 years in captivity,[26][36] and up to 9 years in the wild.[20]
No major threats to bat-eared fox populations exist, though hunting, disease and drought can threaten individuals and lower population numbers on a short term scale.[3] Diseases that affect the bat-eared fox includecanine distemper,canine parvovirus, andrabies.[22] Predators to the bat-eared fox are mostly large mammaliancarnivores, but they are also prey to largeraptors and theCentral African rock python.Black-backed jackals pose the greatest threat to young bat-eared foxes, but in breeding areas, adults will engage inmobbing behavior to drive them off.[4]
The bat-eared fox has some commercial use forhumans. They are important forharvester termite population control, as the termites are considered pests. They have also been hunted for their fur byBotswana natives.[4] Captive bat-eared foxes are present in zoos in North America, South Africa, Europe, and Asia.[3]
^abWerdelen, Lars and Peigné, Stéphanie (2010). "Carnivora". In Werdelin, Lars and Sanders, William Joseph (eds.).Cenozoic Mammals of Africa. University of California Press. pp. 609–612.ISBN978-0-520-25721-4.
^abSkinner, J. D. and Chimimba, Christian T. (2005).The Mammals of the Southern African Sub-region. Cambridge University Press.ISBN978-0-521-84418-5.
^Miller, W.T. (1972).The Flesh-eaters: A Guide to the Carnivorous Animals of Southern Africa. Purnell.ISBN978-0-360-00166-4.
^abcdNel, J. A. J. and Maas, B. (2004)."Bat-eared foxOtocyon megalotis"(PDF). In Sillero-Zubiri, Claudio; Hoffmann, Michael; and Macdonald, David W. (eds.).Canids: foxes, wolves, jackals, and dogs. Gland, Switzerland: IUCN/SSC Canid Specialist Group.ISBN978-2-8317-0786-0. Archived fromthe original(PDF) on 1 September 2012.
^Hartstone-Rose, Adam; Kuhn, Brian F.; Nalla, Shahed; Werdelin, Lars; and Berger, Lee R. (February 2013). "A new species of fox from the Australopithecus sediba type locality, Malapa, South Africa".Transactions of the Royal Society of South Africa.68 (1):1–9.Bibcode:2013TRSSA..68....1H.doi:10.1080/0035919X.2012.748698.S2CID84695745.
^Wang, Xiaoming and Tedford, Richard H. (2010).Dogs: Their Fossil Relatives and Evolutionary History. Columbia University Press.ISBN9780231135290.
^Werdelin, Lars and Sanders, William Joseph (2010).Cenozoic Mammals of Africa. University of California Press. p. 612.ISBN9780520257214.
^abNowak, Ronald M.; Macdonald, David W.; and Kays, Roland (2005).Walker's Carnivores of the World. Baltimore: Johns Hopkins University Press.ISBN978-0-8018-8033-9.
^abcSheldon, Jennifer W. (1992).Wild Dogs: the Natural History of the Nondomestic Canidae. San Diego: Academic Press, Inc.ISBN0-12-639375-3.
^abcKieser, J.A. (May 1995). "Gnathomandibular Morphology and Character Displacement in the Bat-eared Fox".Journal of Mammalogy.76 (2):542–550.doi:10.2307/1382362.JSTOR1382362.
^Hinds, David S. (August 1973). "Acclimatization of Thermoregulation in the Desert Cottontail, Sylvilagus audubonii".Journal of Mammalogy.54 (3):708–728.doi:10.2307/1378969.JSTOR1378969.PMID4744934.
^Trappe JM, Claridge AW, Arora D, Smit WA (2008). "Desert truffles of the Kalahari: ecology, ethnomycology and taxonomy".Economic Botany.62 (3):521–529.doi:10.1007/s12231-008-9027-6.S2CID34319584.
^abWilson, Don E. and Mittermeier, Russell A. (2009). "Canidae".Handbook of the Mammals of the World. Vol. 1. Barcelona:Lynx Edicions. pp. 435–436.
^abNel, J.A.J. (1978). "Notes on the food and foraging behavior of the bat-eared fox,Otocyon megalotis".Bulletin of Carnegie Museum of Natural History.
^Hunter, L. and Barrett, P. (2020).Field Guide to Carnivores of the World (2nd ed.). Bloomsbury Publishing.ISBN978-1-4729-8267-4.
^Ferrell, Brandon and Evans, Kristine O. (2022),"Aardvark", in Vonk, Jennifer and Shackelford, Todd K. (eds.),Encyclopedia of Animal Cognition and Behavior, Cham: Springer International Publishing, pp. 1–4,doi:10.1007/978-3-319-55065-7_838,ISBN978-3-319-55064-0, retrieved22 November 2024
^Wright, Harry William Yorkstone (2006). "Paternal den attendance is the best predictor of offspring survival in the socially monogamous bat-eared fox".Animal Behaviour.71 (3):503–510.doi:10.1016/j.anbehav.2005.03.043.S2CID53148426.
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