Cercocebus chrysogaster

(Cercocebus agilis chrysogaster /

C. galeritus chrysogaster)

1900                 C. agilis chrysogaster by Lydekker

1900                 C. chrysogaster by Lydekker

1993                 C. agilis chrysogaster by Wilson and Reeder

2006                 C. chrysogaster by IUCN/SSC Primate Specialist Group

 The English translation for the Latin "agilis" is "agile, nimble, active".

 The English translation for the Latin "chrysogaster"; "chrysos" is "gold" and "gaster" is "stomach", hence the common name.

 Information From the Wild

Distribution in 1900 was said to be only in the Democratic Republic of Congo – formerly Zaire (Groves, 1978).  With what limited information exists today, C. chrysogaster seems to be localized in the Lukenie-Sankuru area of central DRC and perhaps to the west and north of this area as well. Information about habitat preference, diet and behavior in the wild can only be extrapolated from the other C. galeritus or C. agilis subspecies.  Therefore it is assumed they live in seasonally flooded areas, are semi-terrestrial (their marked sexual dimorphism supports this) and omnivorous.Sexual dimorphism is slightly more exaggerated for this subspecies in comparison to C. agilis (Dorst, Dandelot, 1970; Groves, 1978).

Description

  Pelage is similar to that of C. agilis.  The hair on the back and the outer portions of the limbs are agouti-banded with an overall olive to olive-brown coloration.  There is a slight dorsal stripe in some individuals. The underside of the abdomen ranges from yellow to a bright orange. The underside of the limbs and neck are usually a white to cream-color (Sacramento Zoo). The skin of the hands and face are dark brown with unpigmented upper eyelids. The light hair bases, swept back from the cheeks give a slight white border to the face.  No whorl above the forehead and only minimal amounts of hair lying forward over the brow (Sacramento Zoo). No crest of hair from the forehead as with C. g. galeritus and C. g. sanjei.

In Captivity - North American Region

  Since 1953, 59 individuals in this regional studbook. Current population is 16 individuals. Due to old exhibit design (small exhibits and den areas), C. chrysogaster has been historically kept in pairs and pairs with offspring.  Only in the last 5 years have trios and groups been attempted, but with mixed success.  The age of the individuals may be an important factor to the success of group introductions. Sexual dimorphism is marked with adult males ranging in weight from 11 kg (24 lb) to 15 kg (33 lb) and head to tail base is approximately 53 cm (21 in) with tail length approximately 54 cm (22 in).  Males become sexually dimorphic beginning at approximately 5 years of age (Sacramento Zoo, weight records). Mature males are not only larger in size than females but are also very thickset in appearance. Adult females weigh approximately 8 kg (18 lb) and head to tail base is approximately 44 cm (17.5 in) with tail length 45 cm (18 in) (Sacramento Zoo). From data recorded at the Sacramento Zoo, females begin cycling at approximately 2.5 years of age but do not conceive until the age of 5 years. (The first cycle has always begun with a perineal swelling, then the first menses.)  Perineal swellings are cyclic at approximately 30 days and certain stress factors can elongate the cycle up to 140 days (Sacramento Zoo, 1994).  Menses is variable (2 to 5 days) between individuals and is very visible.

  Gestation is approximately 174 – 179 days.  If conception occurs during peak perineal swelling (at ovulation), there is usually an immediate deflation. There have been two documented cases of post-conception perineal swellings (at Day 46 and 48) as has been observed in C. g. galeritus and C. a. atys, C. a. lunulatus and C. torquatus.  Slight perineal swellings, implantation bleeding and perineal color changes have all been noted during pregnancy, but have not been fully documented.  Weight at birth of one individual was 0.75 kg (1.7 lb) (Charles Paddock Zoo, 1993). No birth seasonality has been observed and no twin births have been recorded in this region.  Young are born with pale skin on the hands, feet and face, adult coloration on their backs but possess a black head.  By 2 months of age, a band of gold forms at the top of the forehead and moves back over time to the neck, creating the full agouti pelage of the adults. The face begins to darken at 14 weeks (Sacramento Zoo). Vocalizations such as alarm calls, copulation vocalizations and territorial spacing calls have all been documented.  Facial demonstrations and body posturing appear to be very important and common communication mediums (Sacramento Zoo). Threat gestures can be accentuated by raising the eyebrows, therefore exposing the non-pigmented are above the eyes.