Ecologie et vie sociale de Nandinia binotata (Carnivores, Viverrides) : comparaison avec les prosimiens sympatriques du Gabon

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The African palm civet Nandinia binotata is an arboreal Viverrine, nocturnal in habits, whose diet consists of both fruits and insects. The species was studied in North-east Gabon from 1965 to 1973, in the same 6 km² area where we have observed five sympatric species of nocturnal prosimians (Charles-Dominique, 1971-1978). Forty five individuals were caught and individually marked from 1971 to 1973. Twenty-eight of them were equipped with a radio transmitter and their movements followed in the subsequent months. The African palm civet lives in various forest types, where it is found mainly between 10 to 30 m above ground level. This civet mainly uses large branches and lianas (1 to 35 cm in diameter), whereas the three species of prosimians sharing the same kind of habitat prefer smaller branches, more vertically oriented. The cornified areas of the feet are used to grasp the large vertical branches, especially when the animal is climbing down. The African palm civet very rarely ventures on the ground. Nandinia binotata spends the day time sleeping on a fork, a large branch or in a bundle of lianas. Weakened or injured individuals tend to be active both by day and by night, spending more time on the ground. Fruits are the staple food of this Viverrine, on average forming 80 % of the stomach contents. However seven of the twenty-two stomachs examined contained small quantities of prey, such as rodents, bird eggs, large beetles or caterpillars. Compared to other sympatric Carnivores, the population density of the African palm civet is high (about 5/km2 )and its biomass in the study area is close to that of frugivorous prosimians. Three age categories are recognized in the population, based upon body weights and dental characteristics. Sexual maturity occurs during the third year of life. Adult females territories (averaging 45 ha) are contiguous. Some of their border areas are scent-marked with the perineal gland secretion of the animal, as are fruiting trees within the territories. Adult females do not tolerate trespassing of territorial boundaries by other adult females, but do tolerate immature females (which are often their own daughters) at least as long as they are sexually immature. The situation is more complex among males. Dominant adult males hold large territories (about 100 ha on the average) which overlap a number of female territories. Trespassing by other large adult males is not tolerated, whereas smaller adult males are allowed to stay in the territory, but not to have access to females. Young males leave their mothers’ territories as soon as they are weaned. On the whole, body size, size of the testes and development of the perineal gland are correlated with social hierarchy among males. Territorial fights between males or between females may be serious affairs ; one of the protagonists can die. Mating takes place during the visits paid by the dominant adult male to the females settled within the limits of its own territory. At that time loud calls are exchanged between adults of both sexes. The ecology and social structure of the African palm civet is compared with those of sympatric nocturnal prosimians. Fifteen species of nocturnal and arboreal mammals share the same mixed diet of fruits and insects in the study area. However, the pressure of competition is lessened by differences in body-size. The similarities between the social life of the Palm civet and that of the nocturnal prosimians are emphasized.