Cephalophus rufilatus [Gray, 1846]
- Citation: Ann. Mag. Nat. Hist., [ser. 1], 18:166
- Type locality: Sierra Leone, Waterloo Village
The taxonomic record (above) is taken from Wilson and Reeder (1993). The red-flanked duiker is included in the subgenus Cephalophorus [Gray, 1842] (Nowak, 1991). Heyden (1963) combined C. rufilatus into a superspecies with C. nigrifrons due to similarities in skull structure, but the two are generally considered to be distinct on the basis of coloration and sympatry in distribution (Wilson, 1987; Kingdon1, 1982). Depending on the author, this species is either considered monotypic or divided into two subspecies: the western C. r. rufilatus ranging from Senegal to the Chari and Benue valleys, and the eastern C. r. rubidior, found from the Chari river valley eastward (Kingdon, 1997). Synonyms include C. rubidior and C. cuvieri (Wilson and Reeder, 1993).
The red-flanked duiker is a small duiker; head and body length averages 70 cm and shoulder height is just over 35 cm. The legs are relatively short and the back is rounded, giving this duiker a very squat appearance. Adult weight is between 9 and 14 kg.
|Reported measurements for red-flanked duiker (Cephalophus rufilatus) |
|Source ||Adult Weight ||Head & Body Length ||Shoulder Height ||Tail Length |
|Happold, 1987 ||11 - 13.5 kg ||66 cm ||36 cm ||10 cm |
|Kingdon, 1982 ||12-14 kg ||75-80 cm ||35-38 cm ||8-9 cm |
|Kingdon, 1997 ||6-14 kg ||60-80 cm ||30-38 cm ||7-10 cm |
|Walther, 1990 ||9-12 kg ||60-70 cm ||30-40 cm ||7-10 cm |
|Wilson, 1987 ||9-12 kg ||60-70 cm ||- ||7-10 cm |
The red-flanked duiker is an overall orange-rufous color, with no marked difference in coloration on the belly (Happold, 1987). A very broad strip of bluish-gray pelage marks the mid-dorsal line; unlike many other duikers, this stripe lacks sharp borders and instead gradually merges with the rufous pelage on the upper flanks (Happold, 1987; Wilson, 2001). This dorsal band is darker in the eastern subspecies (C. r. rubidior) than in the western race (C. r. rufilatus) (Kingdon, 1982). The lower legs are dark blue-gray in color (Kingdon, 1982; Wilson, 2001). The narrow tail is 7-10 cm long and ends with a black tuft (Happold, 1987).The face is generally rufous, with a bluish or blackish blaze extending from the forehead to the muzzle; in some individuals, there is considerable interspersion with red hairs, while the blaze may be quite dark in others (Happold, 1987, Wilson, 2001). As with the dorsal stripe, this blaze has indistinct borders. The dark nose and black lower lip contrast sharply with the white upper lip and underside of the jaw (Kingdon, 1982). The prominent preorbital glands are indicated by a large slit in front of each eye (Happold, 1987). The profile of the nose is straight, and the skull is narrow (Kingdon, 1982). The ears are wide and relatively large, approximately 7 cm long (Kingdon, 1982). The back sides of the ears are dark brown to black, while the edges and insides have prominent white markings (Happold, 1973; Happold, 1987; Kindgon, 1982).There is a vertical tuft of dark hair on the forehead (Happold, 1987; Kingdon, 1982; Walther, 1990). The horns are simple spikes, being smooth and pointed in the same plane as the forehead (Happold, 1987). They are always present in males, but are often absent in females or hidden in the forehead crest (Happold, 1987; Wilson, 1987). Reported horn lengths vary, but representative values of 6-9.5 cm for males and 3-4 cm for females are given by Walther (1990).
Reproduction and Development
It is unknown whether breeding is seasonal, but young animals are often reported in the dry season or early wet season (Happold, 1987). Gestation length from captive animals may vary from 223-245 days, with two of three reported values being above 240 days (Dittrich, 1970, 1972; in Schweers, 1984). The single neonate weighs approximately 1,000 grams (reported birth weights vary from 760 g - 1,335 g), and is concealed in dense vegetation by its mother (Dittrich, 1969; Dittrich 1979; Happold, 1987; Wilson, 2001). While in this hiding stage, youngsters cache themselves in a prone position and will remain still even if approached closely (Happold, 1987).
Observations in captivity suggest that weaning typically occurs between 93 and 98 days of (average 95 days) (Wilson, 2001). Sexual maturity in females is reached by 18 months, such that their first offspring is produced at 26 months of age (Wilson, 2001). Fecundity is likely high due to the observed maintenance of population numbers despite heavy hunting (Happold, 1987). In captivity, red-flanked duikers may live to 15 years or more (Weigl, 2005).
The red-flanked duiker is the only savanna-adapted member of the genus Cephalophus, inhabiting riverrine/riparian forests and savanna areas near vegetative cover (Agbelusi, 1992; Wilson, 2001). It is never observed in dense forest (Wilson, 2001). Although discussed by some authors as a forest-edge species, red-flanked duikers need only dense vegetation for cover and may therefore be found far from true forest (Kingdon, 1982). Wilson (2001) reports that riparian woodland with an average of 30% cover is the preferred habitat in Ghana. A source of permanent water is an important feature (Wilson, 2001). Population densities in areas of favorable habitat are estimated to be 3-4 animals per km2 (Wilson, 2001).
The red-flanked duiker is a browser, feeding on mostly on leaves (60% of diet) but also on twigs, flowers, and fruits (Agbelusi, 1992). Roots, bark of trees, and grasses have not been recorded in the diet, and this species rarely visits mineral licks (Agbelusi, 1992; Happold, 1987; Henshaw & Ayeni, 1971). Preferred plant food species in Nigeria are Piliostigma thonningii (leaf tips), Combretum sp. (twigs and leaves), Mucuna flagellipes (twigs and leaves, especially in March), and the fruits of Spondias mombin (Agbelusi, 1992). In Ghana, stomach-content analysis performed by Wilson (2001) suggests the most sought-after plants in that region are Ficus capensis, Nauclea latifolia, and Phoenix reclinata. Other dietary species in Nigeria include leaves of Pterocarpus erinaceous, Bridelia micrantha, Vitex domiana, Annoa senegalensis, and Phyllanthus muellerianus, and fruits of Cola milleni, Ficus capensis, Blighia sapida, and Gmellina aborea (Agbelusi, 1992); in Ghana, red-flanked duikers may consume the fruits of Ficus abutilfolia, F. asperifolia, F. glumosa, F. gnaphalocorpa, F. ingues, F. platyphylla, F. sur, and F. thonningii as well as the fruits, flowers, and leaves of Pavetta crassipes (Wilson, 2001). Red-flanked duikers will feed heavily on cultivated crops where present (Wilson, 2001).
These duikers will often follow primates such as tantalus monkeys and baboons foraging in trees, taking advantage of the flowers, fruits, and vegetation that dropped by the primates (Wilson, 2001). In Ghana, such primate-duiker associations have been observed around the trees Uvaria chamae, Xylopia parviflora, Elacis quineensis, Brysocarpus coccincus, Alcornea cordifolia, and Anthocleleista vogelii (Wilson, 2001). In order to reach food that is above their normal reach, red-flanked duikers may stand upright on their hind legs (Wilson, 2001).
Although older accounts provide conflicting reports of the activity periods of this species, the red-flanked duiker is now understood to be primarily diurnal (Agbelusi, 1992; Wilson, 2001). Peaks of activity occur in the early morning and late afternoon, and midday is often spent ruminating in shade (Wilson, 2001).
When feeding, the red-flanked duiker slowly browses from adjacent plants, then will move a short distance away before continuing to feed (Happold, 1987). The head is often carried low when walking, and the tail flicked constantly from side to side (Wilson, 2001). When disturbed, the species rushes with a series of long bounds into cover (Happold, 1987, Wilson, 2001). The alarm call has been described as a shrill bark or loud snort (Happold, 1987; Wilson, 2001).
Red-flanked duikers live singly or in pairs (15% of observations) and tend to be sedentary (Happold, 1987; Henshaw & Ayeni, 1971; Wilson, 2001). On rare occasion, three individuals (male, female, and young) may be sighted together (Wilson, 2001). Each duiker occupies a small home range that may be maintained for many months provided there is no disturbance (Happold, 1987). Within the home range are several favored resting places that are used regularly; latrine areas also appear to be used (Wilson, 2001). Home ranges usually do not overlap between individuals, but it is not agreed whether they constitute true territories (Happold, 1987). The large preorbital glands produce a secretion that is used to mark objects within the home range (Happold, 1987; Kingdon, 1982). Active marking behavior in itself does not imply territoriality, as stated by Kingdon (1982), but Agbelusi (1992) states that red-flanked duikers are highly territorial.
Wooded savannas and Gallery forests in western and central Africa. Dowsett (1993) suggests that C. rufilatus is restricted to savanna-forest transition zones north of the equator, discounting unconfirmed reports of this species in Congo and Gabon.Countries: Benin, Burkina Faso, Cameroon, Central African Republic, Chad, Côte dIvoire, Democratic Republic of the Congo, Gambia, Ghana, Guinea, Guinea-Bissau, Mali, Niger, Nigeria, Senegal, Sierra Leone, Sudan, Togo, Uganda (IUCN SSC Antelope Specialist Group, 2008).
The red-flanked duiker is classified as a species of Least Concern by the IUCN (IUCN SSC Antelope Specialist Group, 2008), and is not listed by CITES. The species appears to be more resilient to habitat loss than other duiker species, likely due to its affinity for more open habitats, and is still widespread across its historical range (Kingdon, 1982; Eves & Bakarr, 2001; IUCN SSC Antelope Specialist Group, 2008). In fact, the clearing of the rainforest in West Africa may be allowing this species to expand its range southwards (IUCN SSC Antelope Specialist Group, 2008). Outside of well-managed areas, red-flanked duikers are threatened by encroachment of agricultural lands and increased hunting pressure (Eves & Bakarr, 2001; IUCN SSC Antelope Specialist Group, 2008). The total population is estimated at 170,000 individuals (East, 1999).