Disease Risk Assessment in African Great Apes Using Geographic Information Systems

This unique study illustrates the potential application of Geographic Information Systems (GIS) to generate hypotheses regarding which African great ape populations, including bonobos (Pan paniscus), chimpanzees (Pan troglodytes), and gorillas (Gorilla gorilla and Gorilla beringei), are at increased risk from human diseases. Human demographic data and core human health indicator data for the African great ape range countries were obtained. Human population density and percent annual human population growth rate were used as combined indicators of environmental stress/vulnerability (as a proxy measure of human–great ape contact), and infant mortality rate (IMR) and healthy life expectancy (HALE) were used as separate indicators of disease burden among the human populations living in the great ape range countries. Cut-off values were determined and, using GIS, these indicators were analyzed to create maps of critical areas (countries) with both environmental stress and high burden of human diseases. When using IMR as the indicator of disease burden, the great ape range countries identified as critical areas included Benin, Guinea-Bissau, Ivory Coast, Liberia, Nigeria, and Tanzania. Cameroon and Uganda were also identified as critical areas when using HALE as the indicator of disease burden; however, Benin was excluded. Validation of these results would allow for targeted interventions thereby maximizing the use of limited resources. Improvements in public health infrastructure in these critical areas would benefit the human populations that have unmet health needs as well as these endangered species.     

Food calling by captive bonobos (Pan paniscus): An experiment

We examined (i) whether bonobos display a specific food-calling behavior when discovering a hidden food resource, (ii) whether the presence of competitors affects this behavior, and (iii) whether food quantity or gender influences its appearance. We carried out experiments (n = 108) within a captive group of eight bonobos at the Animal Park Planckendael (Mechelen,Belgium). We hid highly preferred food items (n = 7 or 25) in their enclosure and recorded vocal behavior and interactions between discoverer and group members. As a control, we gave the same number of items to the individuals when isolated from the group, a situation without potential food competition (n = 38). The only vocalization frequently uttered by the discoverer was the food peep. They uttered food peeps significantly more often when no food competition was possible. The amount of food had no significant influence on whether food peeps were uttered. The same applies to the individuals’ identity or gender. Although the costs of food calling behavior seemed much higher for males, both sexes uttered food calls to the same extent. We hypothesize thai males signal food presence in order to attract potential mates and are willing to give up the discovered food resource in return for sex: sex for food exchange. In contrast, females may vocalize to attract coalition partners. Through these coalitions, they can monopolize food resources vis-à-vis males. It is also possible that females have less reason to suppress food calk, since they are dominant to males. This study suggests that bonobos are able to give shaded signals about their environment and have the potential to communicate this information in order to promote their sexual strategy.     

Australopithecines: Ancestors of the African Apes?

Since australopithecines display humanlike traits such as short ilia, relatively small front teeth and thick molar enamel, they are usually assumed to be related toHomo rather than toPan orGorilla. However, this assumption is not supported by many other of their features. This paper briefly surveys the literature concerning craniodental comparisons of australopith species with those of bonobos, common chimps, humans and gorillas, adult and immature. It will be argued, albeit on fragmentary data, that the large australopiths of East Africa were in many instances anatomically and therefore possibly also evolutionarily nearer toGorilla than toPan orHomo, and the South African australopiths nearer toPan andHomo than toGorilla. An example of a possible evolutionary tree is provided. It is suggested that the evidence concerning the relation of the different australopithecines with humans, chimpanzees and gorillas should be re-evaluated.     

Structure and use of distance calls in wild bonobos (Pan paniscus)

We report the physical structure and use of a distance call (high-hoot) by wild bonobos (Pan paniscus).Although spectrographic analyses reveal high structural variability, the total sample can be subdivided according to the composition of units—the presence or absence of an initial segment—and the range of the lowest harmonic. Analyses of samples from male—female pairs,vocalizing simultaneously and in close proximity, reveal that both animals utter calls in more or less precise temporal alternation but with different spectral ranges. Whether these differences are gender-specific or related to other factors, such as age or the social relations between particular individuals, is not clear. We suggest that (a) individuals of the same party may coordinate their vocal activity on both the temporal and the spectral level and (b) high hootings stimulate emission of equal vocalizations by members of other parties and may increase cohesion among community members. Comparison of a restricted number of spectrograms from known individuals indicates that bonobos may be able to adjust spectral parameters of one type of distance calls (high- hoot) according to corresponding calls of conspecifics.     

Preliminary bonobo and chimpanzee nesting by habitat type in the northern Lac Tumba Landscape,Democratic Republic of Congo

Knowing how habitat determines the distribution of great apes is essential for understanding their ecology and conservation requirements. Habitats in the northern Lac Tumba Landscape where this study was conducted are mostly swamp and flooded forests, which types have been overlooked in many great ape surveys. This study describes and discusses patterns of bonobo and chimpanzee nesting sites across these habitat types in the general scope of habitat use by great apes. Considerable efforts were deployed to survey forests of the Ngiri Triangle (186 km), Bomongo‐Lubengo (126 km) and Bolombo‐Losombo (112 km). Great ape nesting site encounter rates (r) were calculated for Bonobos (r = 0.21 nesting sites km^?1; Bolombo‐Losombo), chimpanzees (r = 0.11 nesting sites km^?1; Ngiri Triangle) and (r = 0.02 nesting sites km^?1; Bomongo‐Lubengo). Swamps and flooded forests dominated the three zones. Nesting sites were at the highest encounter rates in flooded forests; both great ape species were significantly associated with swampy and flood forests. Human signs did not influence the occurrence of nesting sites in these forests. These results confirm findings from other sites where great apes were observed using swamps; they suggest that future surveys include these types of habitat to avoid under‐estimating population sizes.     

A review of terminology on aggregation patterns in bonobos (Pan paniscus)

We review terms that describe the levels of group structure in Pan paniscus.We discuss points of confusion that result from unclear definition of terms, which could lead to inaccurate intra- and interspecific comparisons. We recommend terms that are applicable to captive populations.