Differences between chimpanzee and baboon gastrointestinal parasite communities.

Cross-species infection among humans, chimpanzees (Pan troglodytes) and baboons (Papio spp.) is potentially a significant public health issue in Africa, and of concern in the conservation of P. troglodytes. However, to date, no statistical comparisons have been made between the prevalence, richness and composition of parasite communities in sympatric populations of baboons and P. troglodytes. We compared parasite communities in sympatric P. troglodytes and Papio papio living in a wilderness site, in the Republic of Senegal, West Africa. We asked whether, in the absence of humans, there are significant differences between these hosts in their interactions with gastrointestinal parasites. We tested whether host, location, or time of collection accounted for variation in prevalence, richness and community composition, and compared prevalence across six studies. We concluded that, despite being closely related, there are significant differences between these two hosts with respect to their parasite communities. At our study site, prevalence of Balantidium, Trichuris and Watsonius was higher in P. papio. Papio papio harboured more parasites per host, and we found evidence of a positive association between Trichuris and Balantidium in P. troglodytes but not P. papio.

Living archaeology: artefacts of specific nest site fidelity in wild chimpanzees.

Savanna chimpanzees are known to re-use areas of the landscape for sleep, and patterns of chimpanzee sleeping site re-use are proposed as a referential model for early hominin archaeological site formation. We recorded the prevalence of deformed but healed branches and remnants of dead branches found around fresh nests at the savanna site of Issa in Ugalla, Tanzania. These old nest scars were found in 79% of 112 beds. We also randomly selected potential nesting locations for a subset of 32 beds within the same trees, and found nest scars in only 19% of these "control" locations. We then monitored 275 nests for up to 19 months for decay, regeneration of new branches, and re-use. Of these 275 nest locations, 24% were re-used within the first nine months of monitoring, and most re-use occurred when the nest had already decayed and was not easily visible from the ground. After 18 months, the proportion of specific nest positions re-used increased to 48%. This fidelity is likely a result of the creation of ideally-shaped support structures and supple new growth for mattress material with successive use of nest locations. We propose that specific nest site re-use may not be a direct product of environmental determination, but a result of "niche construction" through formation of good building sites within trees. Environmental modification through construction behaviour may have influenced both chimpanzee and early hominin ranging, and thus leaves behind recognisable patterns of artefact deposition across the landscape.

Primatology: advanced ape technology.

New findings from African rainforests show chimpanzees to have impressively advanced technology. They make tools of vegetation to harvest termites as in East and West Africa, but some apes in Central Africa show different techniques and tool sets geared for different tasks.

Ant fishing by wild chimpanzees is not lateralised.

Right-dominant handedness is unique and universal in Homo sapiens, suggesting that it is a highly derived trait. Our nearest living relations, chimpanzees, show lateralised hand preference when using tools, but not when otherwise manipulating objects. We report the first contrary data, that is, non-lateralised tool-use, for ant fishing as done in the Mahale Mountains of Tanzania. Unlike nut cracking, termite fishing, and fruit pounding, as seen elsewhere, in which most individuals are either significantly or wholly left- or right-biassed, ant fishers are mostly ambilateral. The clue to this exception lies in arboreality; all other patterns of chimpanzee elementary technology are done on the ground. Arboreal tool use usually requires not only that one hand be used to hold the tool, but also that the other hand gives postural support. When the supporting hand is fatigued, then it must be relieved by the other. Terrestrial tool use entails no such trading off. To test the hypothesis, we compared frequency of hand changing with the incidence of major hand support, and found them to be significantly positively correlated. The evolutionary transition from arboreality to terrestriality may have been a key enabler for the origins of human laterality.

Etho-archaeology of manual laterality: well digging by wild chimpanzees.

We present the first indirect test of manually lateralized behaviour in non-human primates, based on wells dug for drinking water by wild chimpanzees (Pan troglodytes schweinfurthii). Apes at Toro-Semliki Wildlife Reserve, in Uganda, dig bimanually in sandy riverbeds, leaving behind paired piles of excavated sand. The volumes of left- versus right-side piles do not differ, suggesting a lack of behavioural laterality, but this needs to be verified by further, direct observational data.

Hand preferences in captive orangutans (Pongo pygmaeus).

The strength of the evidence for population-level handedness in the great apes is a topic of considerable debate, yet there have been few studies of handedness in orangutans. We conducted a study of manual lateralization in a captive group of eight orangutans (Pongo pygmaeus) ranking the degrees of manual preference according to a defined framework. We analyzed five behavioral patterns: eat (one- and two-handed), make/modify tool, oral tool-use, and manual tool-use. Although some individuals showed significant manual preferences for one or more tasks, at the group-level both one-handed and two-handed eating, oral tool-use, and make/modify tool were ranked at level 1 (unlateralized). Manual tool-use was ranked at level 2, with four subjects demonstrating significant hand preferences, but no group-level bias to the right or left. Four subjects also showed hand specialization to the right or left across several tasks. These results are consistent with most previous studies of manual preference in orangutans. The emergence of manual lateralization in orangutans may relate to more complex manipulative tasks. We hypothesize that more challenging manual tasks elicit stronger hand preferences.

Methodology of motor skill and laterality: new test of hand preference in Macaca nemestrina.

Ten female pig-tailed macaques (Macaca nemestrina) were tested for hand preference and hand skill (i.e., speed of performance and error rate). The experimental task was naturalistic, calling for adaptive manual skills and fine manipulation: the monkeys had to remove small food rewards embedded in a vertical array, and precision opposition of thumb and forefinger was needed to extract each pellet. Each monkey was tested 10 times on 10 different days. The results indicated individual hand preference rather than population-level handedness; however, a tendency toward right predominance was found. The results on hand skill showed a relation between error rate and hand preference, as the preferred hand made fewer errors. A different and unexpected finding was obtained when skill was evaluated in terms of speed of performance: in adult subjects the left hand was quicker than the right. Therefore, different kinds of skill showed different patterns in relation to hand preference.

Brief report: Chimpanzees, tools, and termites: New record from Gabon.

Wild chimpanzees (Pan troglodytes) in northeastern Gabon use tools made of vegetation to obtain termites (Macrotermes? nobilis) for food. They mostly use probes in termite fishing, as recorded elsewhere in eastern and far western Africa. This is the first record of termite fishing by the central west African race of chimpanzees. There are signs that they also use stouter tools, perhaps to perforate the mounds of the termites. These new findings further complicate the status of material culture in this species of ape in nature.

Cotton-top tamarins (Saguinus (o.) oedipus) in a semi-naturalistic captive colony.

To test the prediction that the breeding success of captive cotton-top tamarins (Saguinus (o.) oedipus) could be improved by maintaining them in groups whose size and age-sex composition resembled those of wild groups, data were collated from 6.5 years of records from a breeding colony that otherwise had housing and husbandry procedures similar to those of other successful colonies. Group size and composition in the colony closely resembled those of wild groups, and infant survival was the highest yet reported for the species, with 69% of the 124 infants born reared by their parents to adulthood, and a mean surviving litter size of 1.5 infants. Abortion, stillbirth, and parental neglect of infants were rare. Parity had several effects on reproduction: mean litter size decreased, but percentage infant survival increased; interbirth intervals decreased in length; and seasonality in reproduction was more pronounced for the first four litters born to breeding females than for their subsequent litters, with a birth peak in the spring. Although a spacious and complex physical environment, retention of offspring in their natal families until experience of several sets of infant siblings had been obtained, and non-invasive husbandry and research techniques may all have contributed to the colony's success, it seems possible that the improvement over other colonies is due to the resemblance of group composition to those of wild tamarins.

Guinea baboons (Papio papio) at a sleeping site.

Descriptive and quantitative observations were made of wild Guinea baboons (Papio papio) at a regularly used sleeping tree (Ceiba pentandra) in Senegal. Observations concentrated on the transition from darkness before sunrise until the baboons had left the tree. Behavior at sleeping sites is affected by a variety of social and nonsocial factors. Sleeping postures were adjusted during the night and to suit weather conditions. The baboons began to leave the tree earlier before sunrise in the dry season, especially on moonlit mornings. This might reflect increased foraging demands in the dry season. Sleeping parties were larger in the wet season, the difference being mainly due to juveniles. Huddling in the sleeping tree was little affected by weather conditions. The most common sleeping huddles consisted of adult females and young; huddles rarely contained more than one adult male. Although the sleeping tree was a safe refuge from leopards, the first baboon to leave the tree in the morning was usually an adult male. It has been hypothesized that the buildup of intestinal parasites in feces below sleeping trees influences the use of the trees by baboons; this did not occur here.

Tool use by wild chimpanzees (Pan troglodytes) to obtain termites (Macrotermes herus) in the Mahale Mountains, Tanzania.

Wild chimpanzees (Pan troglodytes) used probes made of vegetation to fish for termites (Macrotermes herus) in the Mahale Mountains of western Tanzania. Data on both the artefacts and behavior associated with their use were recorded over a 5-month period. The chimpanzees of one unit group, B Group, were seen four times to use the tools to extract the insects from their mounds. A sample of 290 tools was collected and analyzed in terms of age, seasonality, length, width, class of raw materials, species, methods of making, extent of use, and damage incurred through use. There were differences across groups in tool use in feeding on termites; some could be related to biotic factors, but others appeared to be cultural differences.

Diet of wild chimpanzees (Pan troglodytes verus) at Mt. Assirik, Senegal: I. Composition.

The composition of the diet of a savanna-living population of wild chimpanzees (Pan troglodytes verus) at Mt. Assirik in Senegal is presented. The study site had a prolonged dry season, high temperatures, and vegetation dominated by grasses. Data came from direct observation, fecal specimens, and feeding traces; thus, strict criteria for acceptance of the indirect data were specified. Composition of diet was given in terms of species and family of prey, parts eaten, life-form, type of habitat, and criteria for inclusion. Forty-three species of plants with 60 parts were eaten; mostly fruits, from trees, in woodland. Nine species of animal prey were eaten, mostly social insects. An additional 41 species of plants with 53 parts were classed as likely to be eaten by chimpanzees, mostly on the grounds of their being eaten by sympatric anthropoids. Overall, the diet of the apes at Mt. Assirik resembles that of this species elsewhere in Africa, but the size of the dietary repertoire seems small and the proportion of low-quality foodstuffs high. The latter are mostly time-consuming to collect or tedious to obtain or process, and include underground storage organs.

Biochemical detection of fecal hematin as a test for meat eating in chimpanzees (Pan troglodytes).

Meat-eating by wild chimpanzees has been reported by a number of workers during the last two decades. Direct observation probably underestimates the incidence, even though the behavior occurs relatively infrequently. In 1978, Moreno-Black suggested that fecal analysis over a long period of time is probably the most effective means to determine the incidence of this behavior in wild chimpanzees and other nonhuman primate groups. A method currently employed by a number of fieldworkers involves the recovery of the remains of a carnivorous meal in the animal's feces. This method, however, may also under represent the incidence because of (1) complete digestion of mammalian parts, (2) the unidentifiability of partially digested remains, and (3) the reingestion of feces. This paper reports the results of a laboratory study using a fecal test not subject to these limitations. The test is based on the biochemical detection of hematin, a derivative of hemaglobin which is found in all mamalian tissues. The results of this study reveal that hematin is a reliable indicator of meat consumption. The test is available in a commercially prepared kit, namely HEMOCULT™, which was developed to detect clinically significant amounts of blood in the feces of human patients with presumptive gastrointestinal lesions. This kit has been evaluated with a view to its possible application in the field.

Intestinal parasites of sympatric Pan troglodytes and Papio Spp. at two sites: Gombe (Tanzania) and Mt. Assirik (Senegal).

Experimental and clinical parasitology need natural baselines or "controls". We present normative data intestinal parasite loads in two genera of African primates. Wild Pan troglodytes and Papio spp. were studied at two sites: Gombe in Tanzania (P. anubis) and Mt. Assirik in Senegal (P. papio). Presence or absence of parasites, especially nematodes, was recorded from fecal specimens. Gombe's primates were more often infected than were Mt. Assirik's. At Gombe, but not at Mt. Assirik, chimpanzees seemed to have a higher incidence of infection than baboons. Comparison of three baboon troops yielded apparent differences in prevalence of infection. No differences in infection were found between the wet and dry seasons in Mt. Assirik's chimpanzees.

The intestinal parasites of a community of feral chimpanzees, Pan troglodytes schweinfurthii.

Fecal specimens from 32 champanzees living in Gombe National Park, Tanzania, were examined. Six species of helminths and 2 species of ciliates were found: Probstmayris gombensis File (in press), Strongyloides fuelleborni von Linstow 1905, Necator sp., Oesophagostomum sp., Abbreviata caucasica von Linstow 1902, Trichuris sp., Troglodytella abrassarti Brumpt and Joyeux 1921, and an unidentified ciliate. None of the parasitic infections were heavy. This is the first such survey of the chimpanzee in its natural habitat.

Is primate tool use special? Chimpanzee and New Caledonian crow compared.

The chimpanzee (Pan troglodytes) is well-known in both nature and captivity as an impressive maker and user of tools, but recently the New Caledonian crow (Corvus moneduloides) has been championed as being equivalent or superior to the ape in elementary technology. I systematically compare the two taxa, going beyond simple presence/absence scoring of tool-using and -making types, on four more precise aspects of material culture: (i) types of associative technology (tools used in combination); (ii) modes of tool making; (iii) modes of tool use; and (iv) functions of tool use. I emphasize tool use in nature, when performance is habitual or customary, rather than in anecdotal or idiosyncratic. On all four measures, the ape shows more variety than does the corvid, especially in modes and functions that go beyond extractive foraging. However, more sustained field research is required on the crows before this contrast is conclusive.