Gérard Dubost

Comparative diet of the two forest cervids of the genus Mazama in French Guiana

The diets of the two Amazonian brocket deer (the red brocket Mazama americana and the grey brocket Mazama gouazoubira) were studied in French Guiana through the examination of stomach contents. The two species are mainly frugivore-granivores, even during the annual period of fruit scarcity (56% of the annual diet in red brockets and 68% in grey brockets). Both rely heavily on fruits and seeds, but overcome the fall in fruit availability by eating significant quantities of fibres, leaves and flowers, particularly the red brocket. Seasonal variation in quantity consumed was observed only for gravid females, which suggests that reproduction may be dependent on the fruiting season. Both species took a wide variety of plants (respectively a total of 79 and 107 species, and 8.4 and 8.9 species per stomach on average). They can be considered non-selective feeders, choosing fruits above all according to their abundance, their size, and perhaps their softness. Both species are seed eaters, destroying nearly all seeds ingested. The two species are potential competitors, but their diet competition may be reduced by their large difference in body size and somewhat different ecological niches. These deer are among the most generalized frugivores of the Guianan forest, thus reducing their food competition with other frugivores.

Population characteristics of a semi-free-ranging polytocous cervid, Hydropotes inermis

Abstract Population characteristics of the polytocous Chinese water deer were studied and compared with those of other cervids and small ruminants. Numerous individuals living semi-freely on a large area were followed during 3 consecutive years. Animals were ear-tagged; matings, births and deaths were recorded. Although this captive population lived at high density, body masses were comparable to those of wild individuals, as were body growth, age at sexual maturity, periods of mating and birth, percentages of females giving birth, and death rates at any age. In contrast, litter size and proportion of young in the population were lower. On the whole, water deer differ from most other cervids by several characters corresponding to a high-population dynamic: short gestation, large litter size, reduced suckling phase, rapid body growth, early tooth replacement and sexual maturity, high mortality rate. However, in fact, water deer populations increase less in the wild than those of other species.

Behaviours of collared and white-lipped peccaries (Tayassu tajacu andT. pecari) in relation to sexual receptivity of the female

Changes in behaviours of the two peccary species,Tayassu tajacu Linnaeus, 1758 andT. pecari Link, 1795 between non-receptive and receptive periods were followed by presenting females to males daily for 15 minutes. InT. tajacu, the rank order of behaviours, similar in both sexes during the non-receptive period, differs during receptivity. Contact behaviours decrease in males, whereas sexual ones progress. The same tendency appears in females. Inhibited bites replace markings of partner as the most common behaviour in both sexes. InT. pecari, the rank order of behaviours always differs between sexes. When females become receptive, the differences from the non-receptive period are neither numerous nor significant. The most common behaviour of males, previously markings of partner, becomes mounts, whereas in females agonistic behaviours reinforce their dominance. In this species, the only behaviours that increase are those leading directly to copulation or those of an agonistic nature. In both species, females show more agonistic behaviours than males (mainly inhibited bites inT. tajacu, truly aggressive ones inT. pecari). When females are receptive, males ofT. pecari become less active, contrary toT. tajacu where both sexes double their activity. InT. tajacu, most behaviours vary significantly in relation to the progesterone level, contrary to the other species. These pecularities appear correlated to herd composition and organisation.

Breeding periods of Gerbillus cheesmani (Rodentia, Muridae) in Saudi Arabia

Abstract In deserts, rainfall is rare and often irregular, and this directly conditions the growth, flowering and fruiting of plants. Consequently, food can become seasonally scarce for plant-eating vertebrates. The relationship between the reproduction of rodents, rainfall, and plant production has been partly studied in some Asian and African desert regions, but not in Saudi Arabia. We therefore sought to define the breeding periods of the most common rodent in that country, Gerbillus cheesmani. More than 540 specimens were collected during 16 consecutive months between November 2001 and February 2003. As expected, the reproduction of mature males and females showed significant monthly variation directly correlated to rainfall. Most young were captured 2 months after the peak in pregnancy. The reproduction of this species was clearly seasonal in Saudi Arabia, unlike other desert regions where many rodents reproduce more or less throughout the year. Furthermore, both sexes reproduced synchronously, whereas in most other countries, males become reproductive 1–2 months before females. Lastly, reproduction coincided with the rainfall during the study period, but not with the average pluviosity of the country. This indicates that all the individuals responded quickly to the local conditions.

Reproductive characteristics of the water chevrotain, Hyemoschus aquaticus

Abstract The anatomy of the reproductive organs, sexual maturation, oestrous cycle, mating, gestation and suckling were studied in the water chevrotain, Hyemoschus aquaticus, of Gabon and compared to the known characteristics of other Artiodactyls. A vaginal plug present during the oestrous cycle and throughout gestation appears to be specific to this species. Likewise, the gestation period is relatively long and variable in this species. On the whole, the water chevrotain is similar to other Tragulids, but differs on several points from many Artiodactyl species. In total, among the 24 characteristics present in the water chevrotain and taken into consideration in this study, six could be considered as typical of non-ruminants and five as characteristic of Pecora. Thus, in terms of its reproduction, the water chevrotain (as well as the other Tragulids) is situated between these two taxa, which is in complete accordance with the results obtained in previous studies on its anatomy and behaviour. The proportion of its similarities with non-ruminant species is higher in anatomical than in physiological or ethological characteristics.