Browsing by Author "Hobaiter, Catherine"

Now showing 1 - 6 of 6
  • Thumbnail Image
    Item
    Applying collocation and APRIORI analyses to chimpanzee diets: Methods for investigating nonrandom food combinations in primate self-medication
    (Wiley Subscription Services, Inc, 2024-05) Freymann, Elodie; d'Oliveira Coelho, João; Hobaiter, Catherine; Huffman, Michael A.; Muhumuza, Geresomu; Zuberbühler, Klaus; Carvalho, Susana; Carvalho, Susana
    Identifying novel medicinal resources in chimpanzee diets has historically presented challenges, requiring extensive behavioral data collection and health monitoring, accompanied by expensive pharmacological analyses. When putative therapeutic self-medicative behaviors are observed, these events are often considered isolated occurrences, with little attention paid to other resources ingested in combination. For chimpanzees, medicinal resource combinations could play an important role in maintaining well-being by tackling different symptoms of an illness, chemically strengthening efficacy of a treatment, or providing prophylactic compounds that prevent future ailments. We call this concept the self-medicative resource combination hypothesis. However, a dearth of methodological approaches for holistically investigating primate feeding ecology has limited our ability to identify nonrandom resource combinations and explore potential synergistic relationships between medicinal resource candidates. Here we present two analytical tools that test such a hypothesis and demonstrate these approaches on feeding data from the Sonso chimpanzee community in Budongo Forest, Uganda. Using 4 months of data, we establish that both collocation and APRIORI analyses are effective exploratory tools for identifying binary combinations, and that APRIORI is effective for multi-item rule associations. We then compare outputs from both methods, finding up to 60% agreement, and propose APRIORI as more effective for studies requiring control over confidence intervals and those investigating nonrandom associations between more than two resources. These analytical tools, which can be extrapolated across the animal kingdom, can provide a cost-effective and efficient method for targeting resources for further pharmacological investigation, potentially aiding in the discovery of novel medicines.
  • Thumbnail Image
    Item
    Flexibility in the Social Structure of Male Chimpanzees (Pan troglodytes schweinfurthii) in the Budongo Forest, Uganda
    (Royal Society Open Science, 2022) Badihi, Gal; Bodden, Kelsey; Zuberbühler, Klaus; Samuni, Liran; Hobaiter, Catherine
    Individuals of social species experience competitive costsand social benefits of group living. Substantial flexibility inhumans’social structure and the combination of differenttypes of social structure with fission–fusion dynamics allowus to live in extremely large groups—overcoming some ofthe costs of group living while capitalizing on the benefits.Non-human species also show a range of social strategies todeal with this trade-off. Chimpanzees are an archetypicalfission–fusion species, using dynamic changes in day-to-day association to moderate the costs of within-groupcompetition. Using 4 years of association data from twoneighbouring communities of East African chimpanzees (Pantroglodytes schweinfurthii), we describe an unexplored level offlexibility in chimpanzee social structure. We show thatmales from the larger Waibira community (N=24–31)exhibited additional structural levels of semi-stable core–periphery society, while males from the smaller Sonsocommunity (N=10–13) did not. This novel core–peripherypattern adds to previous results describing alternativemodular social structure in other large communities ofchimpanzees. Our data support the hypothesis thatchimpanzees can incorporate a range of strategies in additionto fission–fusion to overcome costs of social living, and thattheir social structures may be closer to that of modernhumans than previously described.
  • Thumbnail Image
    Item
    Flexible grouping patterns in a western and eastern chimpanzee community
    (Wiley Subscription Services, Inc, 2024-04) Koops, Kathelijne; Akankwasa, Walter; Camara, Henry Didier; Fitzgerald, Maegan; Keir, Alex; Mamy, Gnan; Matsuzawa, Tetsuro; Péter, Hella; Vicent, Kizza; Zuberbühler, Klaus; Hobaiter, Catherine
    Abstract Primate social organizations, or grouping patterns, vary significantly across species. Behavioral strategies that allow for flexibility in grouping patterns offer a means to reduce the costs of group living. Chimpanzees (Pan troglodytes) have a fission‐fusion social system in which temporary subgroups (“parties”) change in composition because of local socio‐ecological conditions. Notably, western chimpanzees (P. t. verus) are described as showing a higher degree of bisexual bonding and association than eastern chimpanzees, and eastern female chimpanzees (P. t. schweinfurthii) are thought to be more solitary than western female chimpanzees. However, reported comparisons in sociality currently depend on a small number of study groups, particularly in western chimpanzees, and variation in methods. The inclusion of additional communities and direct comparison using the same methods are essential to assess whether reported subspecies differences in sociality hold in this behaviorally heterogeneous species. We explored whether sociality differs between two communities of chimpanzees using the same motion‐triggered camera technology and definitions of social measures. We compare party size and composition (party type, sex ratio) between the western Gahtoy community in the Nimba Mountains (Guinea) and the eastern Waibira community in the Budongo Forest (Uganda). Once potential competition for resources such as food and mating opportunities were controlled for, subspecies did not substantially influence the number of individuals in a party. We found a higher sex‐ratio, indicating more males in a party, in Waibira; this pattern was driven by a greater likelihood in Gahtoy to be in all‐female parties. This finding is the opposite of what was expected for eastern chimpanzees, where female‐only parties are predicted to be more common. Our results highlight the flexibility in chimpanzee sociality, and caution against subspecies level generalizations. We used the same motion‐triggered camera technology to compare party size and composition between the western Gahtoy community in the Nimba Mountains (Guinea) and the eastern Waibira community in the Budongo Forest (Uganda). Western chimpanzees were more likely to be in all‐female parties, which is contrary to the expectation of more female‐only parties in eastern chimpanzees. Our findings highlight the flexibility in chimpanzee grouping patterns. Research highlights Party size in western and eastern chimpanzees did not differ between our two study communities suggesting that the number of individuals in a party is shaped by similar socio‐ecological pressures. In our sample, eastern chimpanzees were found to have more males in a party compared to western chimpanzees, contrary to the expectation of more female‐only parties in eastern compared to western chimpanzees. Our findings highlight the flexibility in chimpanzee grouping patterns and caution against subspecies level generalizations from limited data points and/or heterogeneous methods.
  • Thumbnail Image
    Item
    Habitual ground nesting in the Bugoma Forest chimpanzees (Pan troglodytes schweinfurthii), Uganda
    (Wiley Subscription Services, Inc, 2024-02) Hobaiter, Catherine; Klein, Harmonie; Gruber, Thibaud
    We report the presence of habitual ground nesting in a newly studied East African chimpanzee (Pan troglodytes schweinfurthii) population in the Bugoma Central Forest Reserve, Uganda. Across a 2‐year period, we encountered 891 night nests, 189 of which were classified as ground nests, a rate of ~21%. We find no preliminary evidence of socio‐ecological factors that would promote its use and highlight local factors, such as high incidence of forest disturbance due to poaching and logging, which appear to make its use disadvantageous. While further study is required to establish whether this behavior meets the strict criteria for nonhuman animal culture, we support the argument that the wider use of population and group‐specific behavioral repertoires in flagship species, such as chimpanzees, offers a tool to promote the urgent conservation action needed to protect threatened ecosystems, including the Bugoma forest. Chimpanzees of the Mwera community in the Bugoma Central Forest Reserve, Uganda, construct 21% of their overnight nests on the ground, with a further 4% at under 2 m in height. Overnight ground nests can be distinguished from flimsier structures, such as day beds, by the use of multiple interwoven structural branches. Research highlights Chimpanzees in the Bugoma Forest, Uganda, habitually employ overnight ground nests (21% of total nests, ground nests present in 25% of nest sites). We discuss a range of socio‐ecological and cultural explanations, highlighting local factors that appear to be disadvantageous for the behavior. While behavioral variation may offer a powerful tool for conservation, strict scientific thresholds for establishing cultural explanations may not be compatible with urgent conservation timelines.
  • Thumbnail Image
    Item
    Selective deforestation and exposure of African wildlife to bat-borne viruses
    (Nature Publishing Group UK, 2024-04) Fedurek, Pawel; Asiimwe, Caroline; Rice, Gregory K.; Akankwasa, Walter J; Reynolds, Vernon; Hobaiter, Catherine; Kityo, Robert; Muhanguzi, Geoffrey; Zuberbühler, Klaus; Crockford, Catherine; Cer, Regina Z; Bennett, Andrew J; Rothman, Jessica M; Bishop-Lilly, Kimberly A; Goldberg, Tony L.
    Proposed mechanisms of zoonotic virus spillover often posit that wildlife transmission and amplification precede human outbreaks. Between 2006 and 2012, the palm Raphia farinifera , a rich source of dietary minerals for wildlife, was nearly extirpated from Budongo Forest, Uganda. Since then, chimpanzees, black-and-white colobus, and red duiker were observed feeding on bat guano, a behavior not previously observed. Here we show that guano consumption may be a response to dietary mineral scarcity and may expose wildlife to bat-borne viruses. Videos from 2017–2019 recorded 839 instances of guano consumption by the aforementioned species. Nutritional analysis of the guano revealed high concentrations of sodium, potassium, magnesium and phosphorus. Metagenomic analyses of the guano identified 27 eukaryotic viruses, including a novel betacoronavirus. Our findings illustrate how “upstream” drivers such as socioeconomics and resource extraction can initiate elaborate chains of causation, ultimately increasing virus spillover risk. A study in Uganda found that local extirpation of a mineral-rich tree species used in tobacco farming forced wildlife to obtain minerals by eating bat guano, in which 27 eukaryotic viruses were identified, including a novel betacoronavirus.
  • Thumbnail Image
    Item
    Variable Expression of Linguistic Laws in Ape Gesture: A Case Study from Chimpanzee Sexual Solicitation
    (Royal Society open science, 2022) Safryghin, Alexandra; Cross, Catharine; Fallon, Brittany; Heesen, Raphaela; Ferrer-i-Cancho, Ramon; Hobaiter, Catherine
    Two language laws have been identified as consistent patterns shaping animal behaviour, both acting on the organizational level of communicative systems. Zipf's law of brevity describes a negative relationship between behavioural length and frequency. Menzerath's law defines a negative correlation between the number of behaviours in a sequence and average length of the behaviour composing it. Both laws have been linked with the information-theoretic principle of compression, which tends to minimize code length. We investigated their presence in a case study of male chimpanzee sexual solicitation gesture. We failed to find evidence supporting Zipf's law of brevity, but solicitation gestures followed Menzerath's law: longer sequences had shorter average gesture duration. Our results extend previous findings suggesting gesturing may be limited by individual energetic constraints. However, such patterns may only emerge in sufficiently large datasets. Chimpanzee gestural repertoires do not appear to manifest a consistent principle of compression previously described in many other close-range systems of communication. Importantly, the same signallers and signals were previously shown to adhere to these laws in subsets of the repertoire when used in play; highlighting that, in addition to selection on the signal repertoire, ape gestural expression appears shaped by factors in the immediate socio-ecological context.