Cercocebus atys atys
(Cercocebus
torquatus atys)
1758
Chlorocebus by Linnaeus
1797
Simia atys by Audebert
1812
C. fuliginosus by E. Geoffroy
1821
(Cercocebus) aethiopicus by F. Cuvier
2006
C. atys atys by IUCN/SSC Primate Specialist Group
Although they do NOT possess a white collar, one of their scientific names “torquatus”
translates to "wearing a necklace". Sooty mangabeys are often listed as C.
torquatus atys, which would be a subspecies to the Red-capped and
White-crowned mangabeys. All three have their common and scientific names
commonly transposed and misused.
Information From the Wild
Distribution is through Sierra Leone, Liberia, Guinea and Ivory Coast (Groves, 1978). The habitat type is tropical and subtropical moist broadleaf forest which is part of the larger Guinean Moist Forest tract ecoregion. Not a lot of information is available from the wild, however Sooty mangabeys have been studied in the Taï National Park in south-west Ivory Coast (Côte d’Ivoire). The park is 454,000 hectares and is the largest remaining area of primary forest in western Africa. It has an average rainfall of 1830 mm and average temperature of 24 degrees C (75 degrees F). There is a distinct dry season from December – January.
Researchers at the Taï Monkey Project (a study site within the Taï National Park) report that Sooty mangabeys spend up to 65% of their time on the ground. Body weight of males is approximately 11 kg and females 6.5 kg. The multi-male groups can attain a group size of 100 individuals (Range, 1998). Group composition fluctuates seasonally and subgroups form in response to availability of preferred foods. Home range size can approach 8 km2 (Rutte, 1998). Diet consists predominantly of fruits, nuts and hard seeds (68%), many of which are gathered amid the leaf litter on the forest floor. In addition, invertebrates comprise ~ 26% of their diet (Bergmüller, 1998).
Sooty mangabeys in the Taï Forest have also been observed eating frog-spawn. The mangabeys mainly preyed on the clutches of Chiromantis rufescens which attach their foam nests on leaves, branches, tree trunks or rocks above ponds and puddles. The heights of the foam nests range from several centimeters to 20 m off the ground. Observations suggest that the mangabeys knew where to find frog-spawn and intensively checked for it. Mangabeys were even seen jumping into the water in order to harvest clutches on plants growing in the pond. Eating frog-spawn seemed to be done mostly by adult females (Rödel, et al, 2002).
Dominance relations among female Sooty mangabeys were studied in the Taï Forest by Range and Noë (2002). Females were found to stay in their natal group, while new males joined the group (this supports the overall view that mangabey males leave their natal group). Females have been observed to aggressively attack individuals of neighboring groups in intergroup encounters, while males were not observed to participate in such activities. Adult females were found to have well-differentiated social relationships. Those females high in rank associated with other females that were similar in rank (but coalitions between females were rare). The adult females in the study site formed a linear dominance hierarchy, with higher ranking females having increased foraging efficiency at concentrated food resources (by keeping low ranking females to the periphery). West African lowland rainforest has been severely reduced by clearing for agriculture, human settlement and mining activities. In addition, intensive hunting for the bush meat trade is accelerating the loss of this species in the wild. Information about habitat preference, diet and behavior in the wild can only be extrapolated from C. torquatus and C. atys lunulatus. Therefore it is assumed they live in seasonally flooded areas, are semi-terrestrial and omnivorous.
Description
The crown is gray, hairs having a straw band and black tip. No whorl on the crown. Upper parts are a smoky-gray and generally there is no clear dorsal stripe. The head, back and tail are a solid dark gray. The cheeks and underside are a gray-white. The skin of the hands and feet are dark gray. The facial skin is dark gray and flesh-colored, becoming nearly black on the lower half of the nose, muzzle and ears. Upper eyelids are flesh-colored (Houston Zoo).Judging from skull measurements, C. atys atys appears to be less sexually dimorphic than C. torquatus (Groves, 2001). It is believed by many that C. atys should be a distinct form from C. torquatus (Groves, 2001).
In Captivity - North American Region
Since 1933 there have been 162 individuals associated to this region. Current population is 4 individuals. Historically, this subspecies has been kept in pairs and single-male, multi-female groups with offspring.
Sexual dimorphism is marked with males larger than females. In comparison to C. torquatus or C. agilis, mature males of this subspecies are not as thickset in appearance. Stabenfeldt and Hendrickx (1973) reported that gestation is 167 days. As with C. torquatus, C. agilis chrysogaster and C. galeritus galeritus, this subspecies demonstrates the occurrence of post-conception perineal swelling near the end of the first trimester. This is thought to confuse paternity, therefore decreasing the chance of infanticide by males in the group (Kinnaird, 1990). No birth seasonality has been observed and no twin births have been recorded in this region. There are currently C. atys atys in captivity in Europe (Field, pers. comm.).