Kibale National Park Research Articles

A chimpanzee enamel-diet δ13C enrichment factor and a refined enamel sampling strategy: Implications for dietary reconstructions

Reconstructing diets from stable carbon isotopic signals in enamel bioapatite requires the application of a δ13C enamel-diet enrichment factor, or the isotopic offset between diet and enamel, which has not been empirically determined for any primate. In this study, an enamel-diet enrichment factor (ε∗enamel-diet) of 11.8 ± 0.3‰ is calculated for chimpanzees (Pan troglodytes) at Ngogo in Kibale National Park, Uganda, based on a comprehensive isotopic assessment of previously analyzed dietary plant data and new isotopic analyses of enamel apatite. Different enamel sampling methods are evaluated to determine the potential influence of weaning on isotopic enamel values and dietary interpretations. The new chimpanzee enrichment factor and a sampling strategy that excludes teeth that formed before weaning completion are applied to all known chimpanzee δ13Cenamel data, either previously published or newly derived in this study, resulting in a dietary range of almost 6‰ across all chimpanzees sampled. This new chimpanzee enamel-diet enrichment factor is then used to reassess dietary reconstructions of 12 fossil hominin species whose isotopic enamel signatures have been determined. Results reveal hominin diets that are isotopically more positive than previously reconstructed, highlighting the widespread contribution of 13C-enriched C4/crassulacean acid metabolism (CAM) resources in fossil hominin diets and emphasizing the broad use of these resources during human evolution. These findings stress the importance of ascertaining and employing an appropriate enrichment factor for dietary reconstructions of specific taxa as well as standardizing the sampling protocol for tooth enamel in isotopic paleodietary reconstructions.

Maternal feeding benefits of allomaternal care in black-and-white colobus (Colobus guereza).

Caring for infants involves lactation, protection, provisioning, and carrying-all energetically taxing states for primate mothers. Holding and carrying clinging infants often constrains mothers from moving and traveling, potentially reducing their food and energy intake; however, when separated from its mother an infant is at risk of predation. This separation therefore requires that mothers be vigilant, further deterring them from feeding. Allomaternal care (AMC) is hypothesized to allow mothers to safely detach from their infants to feed, permitting them to increase energy intake, which is particularly needed for lactation. We examined the nutritional benefits of AMC in black-and-white colobus monkeys (Colobus guereza) by estimating energy intake by lactating mothers during AMC versus non-AMC. We studied seven mother-infant dyads in three groups of C. guereza during six months in Kibale National Park, Uganda. Immature group members handled infants more often than adults, and females handled infants more often than males. An infant's distance to its mother and its nearest neighbor's age and sex best predicted the occurrence of AMC. Lactating mothers fed more often, fed and rested for longer durations, and consumed more metabolizable energy during AMC compared to when they were caring for their infants. These results demonstrate that AMC in C. guereza provides mothers with feeding opportunities that increase their energy intake.

Fruit trees drive small‐scale movement of elephants in Kibale National Park, Uganda

AbstractUnderstanding what motivates animal spatial behavior requires discerning the relationship between animals and the landscape in which they move. Many studies have focused on large scale trends that drive migrations and movement across broad landscapes, but few studies have focused on drivers of local movement within smaller areas based on fine‐scale landscape heterogeneity. This is especially true for African elephants (Loxodonta africana), whose movements in relation to landscape variables have frequently been studied across vast areas, but infrequently on a small scale. We report on how the local distribution of an important resource—fruit trees—shapes elephant movement patterns in Kibale National Park, Uganda. We hypothesized that the spatial location of elephant trails, and especially intersections in the network of trails, would be heavily associated with fruit trees, with trail density being higher in areas with greater fruit availability. Elephant trails and nearby fruit trees were mapped within a 64 km2 area within the interior of the Park. Trail and fruit tree sampling were conducted along 16 evenly spaced one‐km control transects and compared to 28.6 km of elephant trails arrayed throughout the park. Fruit tree basal area was higher along trails and at trail intersections. Trail density was also positively correlated with fruit tree density. Fruit trees may thus serve as a determinant of small‐scale elephant movement and could be used to predict patterns of elephant spatial behavior across forested habitat, which has potential implications for elephant management in the area.

A preliminary analysis of wound care and other-regarding behavior in wild chimpanzees at Ngogo, Kibale National Park, Uganda.

Caring for others is a key feature of human behavior. Mothers, fathers, siblings, grandparents, and other group members provide care in the form of provisioning, protection, and first aid. To what extent is other-regarding behavior present in our primate relatives? Here we describe an unusual incident of other-regarding behavior toward an injured juvenile female chimpanzee (Pan troglodytes schweinfurthii) at Ngogo in Kibale National Park, Uganda. After the juvenile received a mild head wound from an adult female, several adolescent and juvenile chimpanzees gathered to touch, lick, and peer at the wound. One adolescent male wiped a leaf across the cut. Another adolescent male later groomed the injured female and briefly carried her. Across a 5-year period, we observed only three other instances of other-directed wound care in chimpanzees, occurring in 4% (4/100) of cases in which we observed individuals with fresh wounds, and 57 other instances of allomaternal carrying. Despite the infrequency of such behaviors, our study adds another chimpanzee field site to the list of those where other-directed wound care has been observed. Observations from wild chimpanzees provide insight into empathy and may inform our understanding of the evolution of other-regarding behavior in humans.

Patterns of female social relationships in a primate with female-biased dispersal

In socially living mammals, females often form highly differentiated and stable social relationships, commonly with genetically related individuals, which leads to social clusters within groups (i.e. matrilines). However, in primates, research on female social relationships commonly focuses on species and populations with female philopatry and the frequent occurrence of affiliative and agonistic behaviours. Therefore, our aim was to investigate the long-term patterns of female social relationships in a primate with female-biased dispersal, where affiliative and agonistic behaviours among females are rare. We analysed 9 years of continuous data from female Ugandan red colobus monkeys, Piliocolobus tephrosceles , in Kibale National Park, Uganda, and used spatial proximity to establish social networks for 3- and 6-month periods. Then, we investigated the differentiation, stability and clustering of social relationships for each of these periods using several approaches. As expected for a primate with female-biased dispersal, our results largely confirmed the absence of temporally stable social relationships and social clusters within the group. However, in about half of the analysed time periods, females formed differentiated social relationships. This indicates that factors other than dispersal patterns and within-group contest competition contribute to the formation of the ephemeral relationships, as measured by spatial proximity, among female red colobus. Therefore, our results on the patterns of female social relationships in a primate with female-biased dispersal provide important empirical insight for the refinements of theories that aim to explain social evolution in mammals. • We analysed female social relationships over 9 years in a female-dispersed primate. • Females formed differentiated relationships during half of the analysed periods. • There was little indication for temporally stable relationships among females. • Females did not form social clusters often observed in primates with matrilines.

Female-directed aggression by adolescent male chimpanzees primarily constitutes dominance striving, not sexual coercion.

Chimpanzees (Pan troglodytes) are notable for exhibiting high levels of male-to-female aggression. Much of this aggression from adult males serves sexually coercive functions. Despite being smaller and lower-ranking than adult males, adolescent males also engage in regular aggression against adult females. Here, we test whether the primary function of this aggression is sexual coercion, as in adult males, or, alternatively, whether adolescent males use aggression to establish social dominance over females. We analyzed 1771 copulations and 1812 instances of male-initiated aggression between adolescent males (aged nine through 14 years) and adult females across 21 years of observation of the Kanyawara chimpanzee community in Kibale National Park, Uganda. Our test of the sexual coercion hypothesis revealed that adolescent males did not selectively target cycling females for aggression, nor did aggression against cycling females predict rates of copulation with those females. Our test of the social dominance hypothesis showed that males succeeded in dominating all adult females before, or soon after, dominating their first adult male. Additionally, we found that adolescent males dominated females approximately in the order of the females' own ranks, from the bottom to the top of the female hierarchy. Our data illustrate that the establishment of social dominance was more important than sexual coercion in explaining patterns of adolescent male aggression toward females. In comparison, evidence for sexual coercion was clear and compelling in adult males. These findings highlight that the primary function of male-to-female aggression differs between adolescent and adult males.

Urinary neopterin of wild chimpanzees indicates that cell-mediated immune activity varies by age, sex, and female reproductive status

The study of free-living animal populations is necessary to understand life history trade-offs associated with immune investment. To investigate the role of life history strategies in shaping proinflammatory cell-mediated immune function, we analyzed age, sex, and reproductive status as predictors of urinary neopterin in 70 sexually mature chimpanzees (Pan troglodytes) at Ngogo, Kibale National Park, Uganda. In the absence of clinical signs of acute infectious disease, neopterin levels significantly increased with age in both male and female chimpanzees, as observed in humans and several other vertebrate species. Furthermore, males exhibited higher neopterin levels than females across adulthood. Finally, females with full sexual swellings, pregnant females, and post-reproductive females, the oldest individuals in our sample, exhibited higher neopterin levels than lactating females and cycling females without full swellings. Variation in females’ neopterin levels by reproductive status is consistent with post-ovulatory and pregnancy-related immune patterns documented in humans. Together, our results provide evidence of ample variation in chimpanzee immune activity corresponding to biodemographic and physiological variation. Future studies comparing immune activity across ecological conditions and social systems are essential for understanding the life histories of primates and other mammals.

Human-Wildlife Conflict Mitigation Impacts Community Perceptions around Kibale National Park, Uganda

The attitudes of community members living around protected areas are an important and often overlooked consideration for effective conservation strategies. Around Kibale National Park (KNP) in western Uganda, communities regularly face the threat of crop destruction from wildlife, including from a variety of endangered species, such as African elephants (Loxodonta africana), common chimpanzees (Pan troglodytes), and red colobus monkeys (Piliocolobus tephrosceles), as well as other nonhuman primates, including olive baboons (Papio anubis). These frequent negative interactions with wildlife lead many community members to resent the park and the animals that live within it. To mitigate these issues, community members around KNP partnered with researchers to start a participatory action research project to reduce human-wildlife interactions. The project tested four sustainable human-wildlife conflict mitigation strategies: digging and maintaining trenches around the park border, installing beehive fences in swampy areas where trenches could not be dug, planting tea as a buffer, and growing garlic as a cash crop. These physical exclusion methods and agriculture-based deterrents aimed to reduce crop destruction by wild animals and improve conditions for humans and wildlife alike. We conducted oral surveys with members of participating communities and a nonparticipating community that border KNP to determine the impact of these sustainable human-wildlife conflict mitigation strategies on attitudes toward KNP, wildlife officials, and animal species in and around KNP. We found that there is a positive correlation between participation in the project and perceived benefits of living near KNP. We also found that respondents who participated in the project reported more positive feelings about the Uganda Wildlife Authority, the organization that oversees KNP. This research will help inform future conservation initiatives around KNP and other areas where humans and animals face conflict through crop damage.

Deconstructing Protein in the Diet and Biomass of Colobine Primates

Dietary protein is often considered a factor that limits the growth of primate populations. The ratio of crude protein (CP) to fiber in common mature leaves in a forest reliably predicts colobine biomass across Africa and Asia. This relationship is puzzling because CP of mature leaves is notably high in some forests, including Kibale National Park, Uganda, where mature leaves have a higher protein concentration (ca. 18% CP on a dry matter basis) than what is required for primate growth, maintenance, and reproduction. We used an in vitro assay that incorporates the role of fiber and tannins to assess the biological relevance of CP in the leaves that comprise the diets of colobines (Colobus guereza, Piliocolobus tephrosceles) in Kibale (N = 37 spp. mature leaves, 39 spp. young leaves). Relative to CP, available (digestible) protein (AP) concentrations were 50% lower in mature leaves and 38% lower in young leaves, and protein-to-fiber ratios were lower when incorporating AP. Surprisingly, leaf AP did not differ among sites within Kibale, and AP at all sites exceeded primate protein requirements. Future research, particularly in protein-rich forests like Kibale, should consider focusing on fiber, energy, and other nutritional factors to assess the relationship between colobine biomass and leaf nutritional quality. Our study expands on the way that primate ecologists measure protein, integrates several traits into a single currency of AP, and contributes to conservation management plans.

Occurrence of Citropsis articulata in Tropical Forests in Uganda: Implication for Ex Situ Conservation

Citropsis articulata is a medicinal plant that is increasingly threatened by unsustainable methods of harvesting and habitat degradation. Owing to the fact that this plant species is highly utilized for herbal medicine and is currently restricted to a few forest reserves in Uganda, this has significant implications for ex situ conservation. Therefore, the aim of this study was to assess how physiographical factors influence the occurrence and distribution of C. articulata in the three forest reserves in Uganda, namely, Budongo, Mabira, and Kibale National Park. The study was carried out in 15 compartmental sites in each of the three forests. In each compartmental site, 4 plots of 60 m × 60 m were systematically established, and within each plot, 4 subplots each of size 20 m × 20 m were randomly setup. A total of 240 subplots were assessed for occurrence of Citropsis articulata in each forest. The results indicated a significant (p<0.05) variation in the density of C. articulata with the highest recorded in Kibale National Park. Citropsis articulata generally occurred at moderate altitudinal landscapes (overall elevation = 1200.0 ± 20.73 m) with soils that are moderately acidic (overall pH = 5.7 ± 0.10), low in salinity (overall salinity = 84.0 ± 3.84 mg/l), and moderate levels of macro- and micronutrients. Citropsis articulata was generally associated with plant communities dominated by canopy tree species of genera such as Chryosphyllum, Celtis, Markhamia, Cynometra, Lasiodiscus, Trilepisium, Funtumia, and Diospyros, thus suggesting that C. articulata is a shade-tolerant species. Establishing the ecological requirements of this plant species among other things informs the potential for ex situ production of this plant. This will not only provide alternative sources of plant harvest but also go a long way in relieving the current harvest pressures exerted on the conserved wild populations of this plant species.

Aggression, glucocorticoids, and the chronic costs of status competition for wild male chimpanzees

Across vertebrates, high social status affords preferential access to resources, and is expected to correlate positively with health and longevity. Increasing evidence, however, suggests that although dominant females generally enjoy reduced exposure to physiological and psychosocial stressors, dominant males do not. Here we test the hypothesis that costly mating competition by high-ranking males results in chronic, potentially harmful elevations in glucocorticoid production. We examined urinary glucocorticoids (n = 8029 samples) in a 20-year longitudinal study of wild male chimpanzees (n = 20 adults) in the Kanyawara community of Kibale National Park, Uganda. We tested whether glucocorticoid production was associated with dominance rank in the long term, and with mating competition and dominance instability in the short term. Using mixed models, we found that both male aggression and glucocorticoid excretion increased when the dominance hierarchy was unstable, and when parous females were sexually available. Glucocorticoid excretion was positively associated with male rank in stable and unstable hierarchies, and in mating and non-mating contexts. Glucorticoids increased with both giving and receiving aggression, but giving aggression was the primary mechanism linking elevated glucocorticoids with high rank. Glucocorticoids also increased with age. Together these results show that investment in male-male competition increases cumulative exposure to glucocorticoids, suggesting a long-term tradeoff with health that may constrain the ability to maintain high status across the life course. Our data suggest that the relationship between social rank and glucocorticoid production often differs in males and females owing to sex differences in the operation of sexual selection.

Sociosexual behaviour in wild chimpanzees occurs in variable contexts and is frequent between same-sex partners

Abstract Many animals engage in sociosexual behaviour, including that between same-sex pairs. Bonobos (Pan paniscus) are famous for their sociosexual behaviour, but chimpanzees (Pan troglodytes) apparently do not engage in sociosexual behaviour frequently. However, sociosexual behaviour in chimpanzees may have been overlooked. We observed 584 instances of sociosexual behaviour in chimpanzees at Ngogo, Kibale National Park, Uganda during three years of study. All ages and sexes engaged in sociosexual behaviour, which included mounting, touching of genitals, and pressing genitals together. Most sociosexual behaviour was between adult males. Sociosexual behaviour was often during tense contexts, such as subgroup reunions and during territorial behaviour. Among males, grooming and dominance rank relationships do not explain patterns of sociosexual behaviour. Although sociosexual behaviour may be less frequent in chimpanzees than in bonobos, and bonobos remain distinct in their genito-genital rubbing, our findings suggest that sociosexual behaviour is a regular part of chimpanzee behaviour.

Using strontium isotopes to determine philopatry and dispersal in primates: a case study from Kibale National Park.

Strontium isotope ratios (87Sr/86Sr) allow researchers to track changes in mobility throughout an animal's life and could theoretically be used to reconstruct sex-biases in philopatry and dispersal patterns in primates. Dispersal patterns are a life-history variable that correlate with numerous aspects of behaviour and socio-ecology that are elusive in the fossil record. The present study demonstrates that the standard archaeological method used to differentiate between ‘local’ and ‘non-local’ individuals, which involves comparing faunal isotopic ratios with environmental isotopic minima and maxima, is not always reliable; aspects of primate behaviour, local environments, geologic heterogeneity and the availability of detailed geologic maps may compromise its utility in certain situations. This study instead introduces a different methodological approach: calculating offset values to compare 87Sr/86Sr of teeth with that of bone or local environments. We demonstrate this method's effectiveness using data from five species of primates, including chimpanzees, from Kibale National Park, Uganda. Tooth-to-bone offsets reliably indicate sex-biases in dispersal for primates with small home ranges while tooth-to-environment offset comparisons are more reliable for primates with larger home ranges. Overall, tooth-to-environment offsets yield the most reliable predictions of species' sex-biases in dispersal.

Lethal Coalitionary Aggression Associated with a Community Fission in Chimpanzees (Pan troglodytes) at Ngogo, Kibale National Park, Uganda.

Many animals engage in aggression, but chimpanzees stand out in terms of fatal attacks against adults of their own species. Most lethal aggression occurs between groups, where coalitions of male chimpanzees occasionally kill members of neighboring communities that are strangers. However, the first observed cases of lethal violence in chimpanzees, which occurred at Gombe, Tanzania in the 1970s, involved chimpanzees that once knew each other. They followed the only observed case of a permanent community fission in chimpanzees. A second permanent fission recently transpired at Ngogo, Kibale National Park, Uganda. Members of a large western subgroup gradually ceased associating peacefully with the rest of the community and started behaving antagonistically toward them. Affiliation effectively ended by 2017. Here, we describe two subsequent lethal coalitionary attacks by chimpanzees of the new western community on males of the now separate central community, one in 2018 and the second in 2019. The first victim was a young adult male that never had strong social ties with his attackers. The second was a high-ranking male that had often associated with the western subgroup before 2017; he groomed regularly with males there and formed coalitions with several. Other central males present at the start of the second attack fled, and others nearby did not come to the scene. Several western females joined in the second attack; we suggest that female-female competition contributed to the fission. This event highlighted the limits on protection afforded by long-term familiarity and the constraints on costly cooperation among male chimpanzees.

The development of affiliative and coercive reproductive tactics in male chimpanzees.

Like many animals, adult male chimpanzees often compete for a limited number of mates. They fight other males as they strive for status that confers reproductive benefits and use aggression to coerce females to mate with them. Nevertheless, small-bodied, socially immature adolescent male chimpanzees, who cannot compete with older males for status nor intimidate females, father offspring. We investigated how they do so through a study of adolescent and young adult males at Ngogo in Kibale National Park, Uganda. Adolescent males mated with nulliparous females and reproduced primarily with these first-time mothers, who are not preferred as mating partners by older males. Two other factors, affiliation and aggression, also influenced mating success. Specifically, the strength of affiliative bonds that males formed with females and the amount of aggression males directed toward females predicted male mating success. The effect of male aggression toward females on mating success increased as males aged, especially when they directed it toward females with whom they shared affiliative bonds. These results mirror sexual coercion in humans, which occurs most often between males and females involved in close, affiliative relationships.

Opportunities for respiratory disease transmission from people to chimpanzees at an East African tourism site.

Respiratory illnesses, including COVID‐19, present a serious threat to endangered wild chimpanzee (Pan troglodytes) populations. In some parts of sub‐Saharan Africa, chimpanzee tracking is a popular tourism activity, offering visitors a chance to view apes in their natural habitats. Chimpanzee tourism is an important source of revenue and thus benefits conservation; however, chimpanzee tracking may also increase the risk of disease transmission from people to chimpanzees directly (e.g., via aerosol transmission) or indirectly (e.g., through the environment or via fomites). This study assessed how tourist behaviors might facilitate respiratory disease transmission at a chimpanzee tracking site in Kibale National Park, Uganda. We observed tourists, guides, and student interns from the time they entered the forest to view the chimpanzees until they left the forest and noted behaviors related to disease transmission. Common behaviors included coughing, sneezing, and urinating, which respectively occurred during 88.1%, 65.4%, and 36.6% of excursions. Per excursion, individuals touched their faces an average of 125.84 ± 34.45 times and touched large tree trunks or branches (which chimpanzees might subsequently touch) an average of 230.14 ± 108.66 times. These results show that many pathways exist by which pathogens might move from humans to chimpanzees in the context of tourism. Guidelines for minimizing the risk of such transmission should consider tourist behavior and the full range of modes by which pathogen transmission might occur between tourists and chimpanzees.

The Smart Forest Conundrum: Contextualizing Pitfalls of Sensors and AI in Conservation Science for Tropical Forests

The term ‘smart forest’ is not yet common, but the proliferation of sensors, algorithms, and technocentric thinking in conservation, as in most other aspects of our lives, suggests we are at the brink of this evolution. While there has been some critical discussion about the value of using smart technology in conservation, a holistic discussion about the broader technological, social, and economic interactions involved with using big data, sensors, artificial intelligence, and global corporations is largely missing. Here, we explore the pitfalls that are useful to consider as forests are gradually converted to technological sites of data production for optimized biodiversity conservation and are consequently incorporated in the digital economy. We consider who are the enablers of the technologically enhanced forests and how the gradual operationalization of smart forests will impact the traditional stakeholders of conservation. We also look at the implications of carpeting forests with sensors and the type of questions that will be encouraged. To contextualize our arguments, we provide examples from our work in Kibale National Park, Uganda which hosts the one of the longest continuously running research field station in Africa.

Case study of participatory action research for wildlife conservation

AbstractNegative interactions between humans and wildlife create one of the greatest threats to biodiversity conservation. When wild animals damage the crops in agricultural fields, subsistence farmers suffer food insecurity and economic instability. Animals can be killed or injured during these interactions, and communities may develop negative feelings about conservation. To address conservation concerns, projects should look at both sides of these interactions. A Participatory Action Research approach allows researchers and community members to work collaboratively to investigate and take action in response to this issue. Our team developed a community project to determine residents' perceptions of the benefits and costs of living around Kibale National Park, Uganda, and to implement changes to mitigate those costs. During our initial survey in 2015, we found that over 80% of our 114 respondents were subsistence farmers with no other source of income. All respondents felt that crop damage by wild animals was the biggest problem with living near the park, and they had negative feelings about the park and animals. Thus, we worked with project participants to establish the following land‐use changes throughout 2016 and 2017: (a) planting garlic as a cash crop, (b) planting tea as a buffer crop, (c) building beehive fences, and (d) maintaining a trench around the boundary of the park. Through monthly surveys, we assessed the success of these changes on reducing crop damage and improving conservation initiatives. Compliance with land‐use changes was significantly associated with a reduction in the events of crop damage, which has implications for economic stability and an individual's attitude about conservation. This project provides guidelines for using Participatory Action Research methods to develop sustainable interventions to improve human‐wildlife interactions.

<Note>COVID-19 and chimpanzees from a field perspective: Mitigation measures, ecological and economical situation after four months in Sebitoli, Kibale National Park, Uganda

<Note>COVID-19 and chimpanzees from a field perspective: Mitigation measures, ecological and economical situation after four months in Sebitoli, Kibale National Park, Uganda

Social Network Predicts Exposure to Respiratory Infection in a Wild Chimpanzee Group.

Respiratory pathogens are expected to spread through social contacts, but outbreaks often occur quickly and unpredictably, making it challenging to simultaneously record social contact and disease incidence data, especially in wildlife. Thus, the role of social contacts in the spread of infectious disease is often treated as an assumption in disease simulation studies, and few studies have empirically demonstrated how pathogens spread through social networks. In July–August 2015, an outbreak of respiratory disease was observed in a wild chimpanzee community in Kibale National Park, Uganda, during an ongoing behavioral study of male chimpanzees, offering a rare opportunity to evaluate how social behavior affects individual exposure to socially transmissible diseases. From May to August 2015, we identified adult and adolescent male chimpanzees displaying coughs and rhinorrhea and recorded 5-m proximity data on males (N = 40). Using the network k-test, we found significant relationships between male network connectivity and the distribution of cases within the network, supporting the importance of short-distance contacts for the spread of the respiratory outbreak. Additionally, chimpanzees central to the network were more likely to display clinical signs than those with fewer connections. Although our analyses were limited to male chimpanzees, these findings underscore the value of social connectivity data in predicting disease outcomes and elucidate a potential evolutionary cost of being social.Supplementary informationThe online version of this article (10.1007/s10393-020-01507-7) contains supplementary material, which is available to authorized users.