Troops Of Macaques Research Articles

Bioacoustic monitoring to determine addiction levels of primates to the human sphere: A feasibility study on Japanese macaques.

Some nonhuman primate species, whose original habitats have been reclaimed by artificial activities, have acquired boldness toward humans which is evident based on the diminished frequency of escape behaviors. Eventually, such species have become regular users of human settlements, and are referred to as "urban primates." Considering this, we developed a noninvasive technique based on bioacoustics to provide a transparent assessment of troop addiction levels in anthropogenic environments, which are determined by the dependence on agricultural crops and human living sphere for their diets and daily ranging, respectively. We attempted to quantify the addiction levels based on the boldness of troops when raiding settlements, characterized by a "landscape of fear" because of the presence of humans as predators. We hypothesized that the boldness of troops could be measured using two indices: the frequency of raiding events on settlements and the amount of time spent there. For hypothesis testing, we devised an efficient method to measure these two indices using sound cues (i.e., spontaneous calls) for tracing troop movements that are obtainable throughout the day from most primate species (e.g., contact calls). We conducted a feasibility study of this assessment procedure, targeting troops of Japanese macaques (Macaca fuscata). For this study, we collected 346 recording weeks of data using autonomous recorders from 24 troops with different addiction levels during the nonsnowy seasons. The results demonstrated that troops that reached the threshold level, at which radical interventions including mass culling of troop members is officially permitted, could be readily identified based on the following behavioral characteristics: troop members raiding settlements two or three times per week and mean time spent in settlements per raiding event exceeding 0.4 h. Thus, bioacoustic monitoring could become a valid option to ensure the objectivity of policy judgment in urban primate management.

Determination of Enteroparasites in Long-tailed Macaques (Macaca fascicularis) of Barangay Sumile, Butuan City, Philippines

Macaca fascicularis are primates known to be reservoirs of enteroparasites. Due to anthropogenic activities, they are experiencing habitat loss, forcing them to move to human settlements, resulting in the transmission of zoonotic diseases. This study aims to identify the enteroparasites present in the three troops of long-tailed macaques of Brgy. Sumile, Butuan City, Philippines, and assess their prevalence and intensity. The formalin-ether concentration technique (FECT) was employed in examining fifty-one macaque fecal samples for enteroparasite detection. Identification was via morphological features, and all samples were positive for one or several species of enteroparasites. Of the six species identified, Eimeria sp. was the most prevalent (76.47%), followed by hookworm (66.67%), Strongyloides sp. (41.18%), Ascaris sp. (29.41%), Balantidium sp. (29.41%), and Fasciola sp. (21.15%), respectively. The highest mean intensity (MI) was recorded in Eimeria sp. (30.71±8.57), followed by hookworm (3.59±0.63), Strongyloides sp. (3.20±0.72), Balantidium sp. (1.86±0.63), Ascaris sp. (1.27±0.34), and Fasciola sp. (1.25±0.45). All three troops in the study area had a 100% prevalence of enteroparasites, with troop 3 having the highest MI (76.20±24.42), followed by troop 2 (28.60±12.52) and troop 1 (26.95±5.29). All parasites found are of medical importance, and the results confirm that long-tailed macaques harbor enteroparasites that may transmit to other animals and humans. The findings help strengthen macaques management to ensure this species’ safety, residents, and visitors.

Antimicrobial resistance profiles in bacterial species isolated from fecal samples of free-ranging long-tailed macaques (Macaca fascicularis) living in Lopburi Old Town, Thailand

Background and Aim:At present, increasing in long-tailed macaques (Macaca fascicularis) population in Lopburi old town caused several problems in its community, in particular with sanitation problem. The present study aimed to explore species distribution and antimicrobial resistance patterns in bacteria isolated from feces of the free-ranging long-tailed macaques (Macaca fascicularis) in Lopburi Old Town, Thailand.Materials and Methods:Fresh fecal samples were collected from October 2018 to July 2019 from seven troops of macaques. Bacterial colonies were identified based on Gram stain and standard biochemical techniques. Sensitivity toward eight different antibiotics, including amoxicillin, amoxicillin-clavulanate, cephalexin, clindamycin, doxycycline, enrofloxacin, erythromycin, and gentamicin, was analyzed using the disk diffusion method.Results:A total of 1050 fecal samples were collected. Five unique bacterial species were identified, including Escherichia coli, Enterobacter spp., Proteus spp., Salmonella Group B, and Citrobacter spp. in 100%, 25.71%, 18%, 1.71%, and 0.57% of the fecal specimens, respectively. Among 70 distinct isolates of E. coli, 63 (93%) were resistant to multiple drugs, including amoxicillin, cephalexin, clindamycin, and erythromycin; one isolate (6%) was resistant to clindamycin only. Furthermore, 17 isolates (94%) of Salmonella Group B were resistant to both clindamycin and erythromycin. Five of the six Citrobacter spp. isolates (83%) were also multidrug-resistant (to cephalexin, clindamycin, and erythromycin); the one remaining Citrobacter spp. isolate (6%) was resistant to both clindamycin and erythromycin. However, a high percentage of E. coli, Salmonella Group B and Citrobacter spp. remained susceptible to amoxicillin-clavulanate, enrofloxacin, and doxycycline.Conclusion:Our findings provide the basic information for the selection of empirical therapy and for the evaluation of the scale of antibiotic resistance associated with macaques living in Lopburi Old Town.

Plasmodium knowlesi and other malaria parasites in long-tailed macaques from the Philippines

BackgroundMacaca fascicularis (long-tailed macaque) is the most widespread species of macaque in Southeast Asia and the only species of monkey found naturally in the Philippines. The species is the natural host for the zoonotic malaria species, Plasmodium knowlesi and Plasmodium cynomolgi and for the potentially zoonotic species, Plasmodium inui. Moreover, other Plasmodium species such as Plasmodium coatneyi and Plasmodium fieldi are also natural parasites of M. fascicularis. The aims of this study were to identify and determine the prevalence of Plasmodium species infecting wild and captive long-tailed macaques from the Philippines.MethodsA total of 95 blood samples from long-tailed macaques in the Philippines were collected from three locations; 30 were from captive macaques at the National Wildlife Rescue and Rehabilitation Center (NWRRC) in Luzon, 25 were from captive macaques at the Palawan Wildlife Rescue and Conservation Center (PWRCC) in Palawan and 40 were from wild macaques from Puerto Princesa Subterranean River National Park (PPSRNP) in Palawan. The Plasmodium spp. infecting the macaques were identified using nested PCR assays on DNA extracted from these blood samples.ResultsAll 40 of the wild macaques from PPSRNP in Palawan and 5 of 25 captive macaques from PWRCC in Palawan were Plasmodium-positive; while none of the 30 captive macaques from the NWRRC in Luzon had any malaria parasites. Overall, P. inui was the most prevalent malaria parasite (44.2%), followed by P. fieldi (41.1%), P. cynomolgi (23.2%), P. coatneyi (21.1%), and P. knowlesi (19%). Mixed species infections were also observed in 39 of the 45 Plasmodium-positive macaques. There was a significant difference in the prevalence of P. knowlesi among the troops of wild macaques from PPSRNP.ConclusionWild long-tailed macaques from the island of Palawan, the Philippines are infected with P. knowlesi, P. inui, P. coatneyi, P. fieldi and P. cynomolgi. The prevalence of these Plasmodium spp. varied among the sites of collection and among troops of wild macaques at one site. The presence of these simian Plasmodium parasites, especially P. knowlesi and P. cynomolgi in the long-tailed macaques in Palawan presents risks for zoonotic transmission in the area.

Daily behavioural activity patterns and reproductive ecology of urban rhesus macaques (Macaca mulatta) in human dominated landscape and its implication in management

We observed behavioural activity patterns, daily movements and reproductive ecology (birth rate, death rate, breeding seasons, mating) of urban rhesus macaques (Macaca mulatta) in man-made environment after their reintroduction in Asola-Bhatti Wildlife Sanctuary, Delhi, India using instantaneous sampling or scan sampling method. The daily activity patterns of rhesus macaques inhabiting in the sanctuary were observed from 6:00 h to 18:00 hrs per day from March 2016 to June 2017. The percentage of each activity was estimated quantitatively and birth rate per female per troop in a year was calculated in total 21 troops of rhesus macaques. Macaques adopted different time slot for maximum utilization of food and space available and we estimated the percent time spent of each activity pattern and their variations in a particular geographic area. Daily average distance travelled was 1.89 km/day and it was restricted to the feeding platforms. Mortality was incredibly low (0.17) and high reproductive success was in females per troop. Number of females per troop was 4.48 on average, mean birth rate was calculated 2.20 per female per troop in a year, gestation length 160 days on average. Breeding seasons were April to June and late August to October, although there was no seasonal variation in daily activity pattern and movement ranges throughout the year in the sanctuary. Our study recommendation will help in reducing human-macaque conflicts in urban areas and will serve as a potential source of information of ecology, behaviour of urban rhesus macaques and their management.

The enigmatic Arunachal macaque: its biogeography, biology and taxonomy in Northeastern India

The purpose of this study was to determine the taxonomic status of an unidentified enigmatic macaque seen by scientists since the late 1990s in Arunachal Pradesh, India. We surveyed 49 troops of enigmatic macaques in four districts of Arunachal Pradesh. The population studied is from the macaque sinica-group as defined by the reproductive organs. The main species-separating trait in the sinica-group is tail length to head and body length ratio that decreases with latitude and elevation. We gathered data on morphology, pelage descriptions, tail to head and body ratios and tail to hind foot ratios from photos and live animals (43 individuals from 36 areas) within the range of and between the two subspecies of the Assamese macaque (Macaca assamensis). We compared the data to six western Assamese macaques and studies of Assamese macaques and related species. We found great variability in tail length, pelage color, facial skin color, and facial and hair patterns. The tail/head-body and tail/foot ratios, although varied, supported the hypothesis that these enigmatic forms were part of a population of Assamese macaques found in the gap between the two subspecies ranges and were not a new species as described earlier. Instead, we found evidence that darker pelage, larger body size, and shorter tails occur at higher elevations and latitudes similar to the general trend in the sinica-group's adaptations to colder climates. Thus, the population may be important for its variation, throwing light on the speciation process and how the northern species of Tibetan macaques evolved from an ancestor similar to the Assamese macaques as adaptations to a colder climate.

A Statistical Modelling Approach to the Occurrence and Timing of Reconciliation in Wild Japanese Macaques

AbstractIn various social species, animals have been observed to share friendly relationships with some group members and to resolve conflicts through reconciliation, the exchange of affiliative behaviour soon after a conflict that functions to restore the relationship between the former opponents. The valuable relationship hypothesis predicts that reconciliation should be observed more often after conflicts between friends. Friendly relationships can be described by three dimensions (i.e. value, security and compatibility); however, research into the relative importance of these dimensions for the occurrence of reconciliation is sparse. Moreover, reconciliation may depend on factors other than the social relationship between opponents including, for example, their social status or the context of the conflict. Our study aimed at analysing which factors are important determinants of reconciliation and at testing the valuable relationship hypothesis, by analysing the relative effects of relationship value, security and compatibility on the occurrence and timing of reconciliation. We collected data on two troops of wild Japanese macaques living on Yakushima Island, Japan, and selected the best predicting variables of reconciliation using linear mixed models. Our results show that reconciliation occurs more frequently, and earlier, after conflicts between opponents who exchange a higher percentage of grooming. Two additional variables related to relationship security and value were selected in the best models: frequency of aggression and of approaches resulting in tolerated co‐feeding. Among the variables not related to relationship quality, distance between opponents at the end of the conflict, kinship, sex of the opponents and context of conflict (i.e. during feeding or social time) were included in our models. Our findings support the valuable relationship hypothesis and, in particular, highlight that the fitness‐related benefits of social relationships (i.e. the relationship value) are important determinants of the evolution of friendly relationships and reconciliation.

Cultured Monkeys

Sixty years ago, the notion that animals could have culture was unthinkable to most behavioral scientists. Today, evidence for innovation, transmission, acquisition, long-term maintenance, and intergroup variation of behavior exists throughout the animal kingdom. What can the longitudinal and comparative study of monkeys handling stones tell us about how culture evolved in humans? Now in its 30th year, the systematic study of stone-handling behavior in multiple troops of Japanese macaques has shown that socially mediated learning is essential to explain the spread, persistence, and transformation of individual behavioral innovations among group members. The integrative research paradigm presented here can be applied to the study of various candidate behavioral traditions in other species.

Food provisioning and stone handling tradition in Japanese macaques: a comparative study of ten troops

By addressing the influence of food provisioning on stone handling (SH), a behavioral tradition in Japanese macaques, this study contributes to the ongoing debate in cultural primatology by asking whether human intervention influences the emergence or propagation of behavioral traditions. SH is a form of object play consisting of the manipulation of stones by performing various behavioral patterns. We tested the hypothesis that the frequency of food provisioning affects the daily performance, form, and context of occurrence of SH by influencing a troop's feeding-related activity budget. We used a standardized observation procedure to investigate SH in ten troops of Japanese macaques. In troops provisioned several times a day, SH was more frequent, longer, and more prevalent during provisioning than nonprovisioning periods. These effects of provisioning were not significant in troops provisioned less frequently. SH was more frequently integrated with food-related activities in troops supplied with food several times a day than in the other troops. Food provisioning may be a key factor in the innovation and transformation phases of the SH tradition in Japanese macaques.

Of stones and monkeys: Testing ecological constraints on stone handling, a behavioral tradition in Japanese macaques

Japanese macaques are known to manipulate stones by displaying various seemingly functionless behavioral patterns, including carrying a stone, rubbing two stones together, or gathering several stones into a pile. This form of solitary object play called stone handling (SH) is a behavioral tradition in Japanese macaques, showing striking intertroop differences in frequency and form. Here, we evaluated two ecologically based hypotheses invoked to account for these differences. We hypothesized that the occurrence and form of SH would be affected by stone availability and the degree of terrestriality. We used standardized sampling methods to assess differences in SH and terrestriality among four captive and six free-ranging troops of Japanese macaques, and determine site-specific stone availability. Although we demonstrated that SH is almost exclusively a terrestrial activity, our comparative analyses showed that the number of stones readily available and the relative amount of time spent on the ground by the macaques were not associated with the intertroop differences in the occurrence of SH. Failure to accept the terrestriality and stone availability hypotheses suggests that the performance of SH and the motivation to engage in this activity are both more diverse and more complex than the direct links to time spent on the ground or the number of stones locally available. Other environmental influences and sociodemographic factors should be jointly considered to identify the sources of variation in SH, as a beginning to better understand the constraints on the appearance and subsequent diffusion of stone-use traditions in nonhuman primates. Am J Phys Anthropol, 2008. (c) 2007 Wiley-Liss, Inc.

Age-related differences in the performance, diffusion, and maintenance of stone handling, a behavioral tradition in Japanese macaques

Identifying the sources of behavioral diversity in non-human primates is vital to understanding the evolution of human behavior. Stone handling (SH, hereafter) is a form of object play consisting of the manipulation of stones by performing various behavioral patterns. This behavior is socially transmitted from generation to generation in Japanese macaques ( Macaca fuscata), as a behavioral tradition. SH behavior in particular may reflect on the origin and evolution of stone-tool material culture. The objective of this study was to assess how group size, age structure, and age- and sex-related differences may account for the substantial intra- and inter-troop variations in SH reported in ten troops of Japanese macaques. Our results supported the hypothesis that patterns of variation in SH across troops reflected variability in group size and composition in age classes. We found that troop size was correlated with the proportion of troop members exhibiting SH simultaneously. The effect of troop size on the synchronized performance of SH may reveal the contagious nature of play. Our results suggest that the age structure of the group may affect the diffusion of SH. As predicted by the surplus energy hypothesis, a major functional hypothesis about play, intra-group variation in SH reflected more age- than sex-related differences. SH mainly occurred and was more frequent in younger than in older individuals, whereas no significant sex differences were found. SH episodes were shorter, more vigorous, and SH patterns were more diverse and less complex in immature than in mature individuals. The present findings reveal that age-related factors and group size may constrain the performance, diffusion, and maintenance of SH within a troop. Contrary to most other socially transmitted stone-tool using behaviors in non-human primates and early hominids, there is no optimal SH pattern. Provided some form of social learning, the non-adaptive nature of SH may allow particular SH pattern preferences to emerge at the group level. Our findings urge the use of an inter-populational comparative approach based on multivariate analyses when addressing the question of the evolution of behavioral traditions in primate and human populations.

Female Defensibility in a Small Troops of Japanese Macaques vis-à-vis Nontroop Males and Copulation on the Periphery of the Troop

I provide data compiled over 4 yr on the mating behavior in small troops of wild Japanese macaques on Yakushima Island. The key parameters are the number of sexually receptive females, the number of nontroop males (NTMs), and copulation on the periphery of the troop. I analyzed the following aspects: 1) changes in the proportion of copulation with high-ranking males (HRMs) and NTMs, 2) variations in factors such as fluctuation in the number of sexually receptive females and troop males and their effects on the number of visiting NTMs, 3) the effect of attempted interruption of mounting series by other males, and 4) some aspects of copulation on the periphery of the troop. Throughout the study, 56% of the total number of females mated most frequently with the α-male in a single mating season. However, the relative mating success of HRMs varied over the years and between individuals. The number of visiting NTMs varied depending on the number of receptive females and troop males. Females tended to mate with the NTMs when they appeared around their troops. The direct effect of interruption of the mounting series by other males is equivocal. The females mated with the low-ranking males (LRMs) and NTMs on the periphery of the troop, which increased the possibility of mounting series ending with ejaculation. Females actively sought opportunities for copulation on the periphery of the troop by moving there or initiating close proximity with LRMs and NTMs there. On Yakushima Island, the mating success of HRMs was not always as high as that predicted by the priority of access model. The injury status of the HRM, the number of visiting NTMs, and female choice are all considered to influence a male’s mating success.

Stone‐tool usage by Thai long‐tailed macaques (Macaca fascicularis)

In January and March of 2005, we conducted surveys of long-tailed macaques at Piak Nam Yai Island, Laem Son National Park (9 degrees N 34-35', 98 degrees E 28'), Ranong Province, situated in southern Thailand. Two of the three troops of long-tailed macaques found on the island were observed using axe-shaped stones to crack rock oysters, detached gastropods (Thais tissoti, Petit, 1852), bivalves (Gafrarium divaricatum, Gmelin, 1791), and swimming crabs (Thalamita danae, Stimpson, 1858). They smashed the shells with stones that were held in either the left or right hand, while using the opposite hand to gather the oyster meat. Some monkeys used both hands to handle the stones. According to Matsuzawa's 1996 hierarchical classification of tool usage (levels 0-3), the tool usage by Thai long-tailed macaques could be characterized as either level 1 (cracking rock oysters with stones) or level 2 (cracking drifting mollusks and crabs with stones by placing them on a rock). Our discovery of stone-tool usage by Thai long-tailed macaques provides a new point of reference for discussions regarding the evolution of tool usage and the material culture of primates.

Snake Species Discrimination by Wild Bonnet Macaques (Macaca radiata)

AbstractWild bonnet macaques (Macaca radiata) were studied in southern India to assess their ability to discriminate non‐venomous, venomous and predatory snakes. Realistic snake models were presented to eight troops of bonnet macaques at feeding stations and their behavior was video‐recorded 3 min before and 3 min after snake exposure. Snakes presented were: (1) venomous Indian cobra (Naja naja) displaying an open hood with ‘eyespots’; (2) venomous common Indian krait (Bungarus caeruleus); (3) non‐venomous green keelback (Macropisthodan plumbicolor); (4) non‐venomous rat snake (Ptyas mucosus); and (5) Indian python (Python molurus) which preys on macaques. Latencies to detect and react to the snakes were evaluated to determine initial responsiveness. Longer‐term assessment was measured as the percentage of time individuals looked at the snakes and monitored the activity of nearby individuals before and after snake detection. All snake models engendered caution and maintenance of a safe distance. Alarm calling occurred only during python presentations. The cobra engendered a startle response or running in the largest percentage of individuals after its detection, whereas the rat snake and python elicited bipedal standing or ambulating to monitor the snakes. We also examined the influence of age on snake recognition. Juveniles and subadults looked at the cobra, krait, and python for a larger percentage of time than adults did; albeit, adults looked at the python substantially longer than at the other snakes. Age differences in behavior suggest that, with the exception of the python, repeated experience with snakes in the wild moderates excitability, consistent with the likely threat of envenomation.

Preliminary Report on the Distribution and Status of Macaques in Thailand

We report here the preliminary results of studies on the distribution and status of five macaque species in Thailand. The latter lies in the center of the Indochinese Peninsula and is an important biogeographical region in SE Asia. We are conducting surveys through out Thailand in the order of questionnaire, census, and capture-and-release fieldwork where feasible. We have determined seven localities of stump-tailed macaques (M. arctoides); 36 localities of long-tailed macaques (M. fascicularis); eight localities of rhesus macaques (M. mulatta); six localities of assamese macaques (M. assamensis); and two localities of pig-tailed macaques (M. nemestrina leonina). Long-tailed and rhesus macaques belong to the same species-group, and are generally distributed allopatrically. The boundary between the two species in NE Thailand appears to lie close to latitude of 16oN. The phenotypic (pelage color and relative tail-length) and genetic characters (mtDNA and TSPY locus) of rhesus macaques resident in the area supposed close to the boundary have been analyzed; the results support the "Hybridization hypothesis" by Fooden ([2000], Fieldiana Zoology 96: 1-180). Troops of long-tailed macaques in Thailand, although their numbers sometimes exceed 1,000 animals, are isolated from other conspecifics. In addition, the genetic disturbance (pollution) introduced by artificial means, e.g., the breeding of released pets and human transfer of macaque troops threatens the innate biodiversity of the Thai macaque species.

Contrast of Estrus in Accordance with Social Contexts Between Two Troops of Wild Japanese Macaques on Yakushima.

I observed estrus in two adjacent troops (A-troop and M-troop) of wild Yakushima macaques during the 1984 mating season. A-troop females showed short and regularly cycling estrus periods, seldom came into estrus simultaneously, and scarcely failed to mate when they were in estrus. In contrast, females of M-troop, which went through troop takeovers during the mating season, demonstrated mate competition and subsequent estrus prolongation. Early in the mating season, constantly four to seven females of M-troop were in estrus simultaneously, competed for troop males (TMs), and some of them failed to mate. Subsequently many non-troop males (NTMs) approached to the troop, estrous females mated with them frequently, and mating harassments by females decreased. Among those NTMs, one dominated all TMs, which was referred to as a troop takeover. Successively three other NTMs dominated both all TMs and the former dominant NTM, and in total, four troop takeovers occurred in M-troop during this mating season. The females continued to be in estrus during the whole episodes. All the conceived females also showed prolonged postconception estrus, and they were neither inactive nor less attractive to males. It was suggested that M-troop females increased their opportunity to mate with NTMs by estrus prolongation, at the cost of female-female mate competition, to incite active male intertroop movement and subsequent troop takeovers.

Research of provisionized wild Japanese monkeys in Yakushima Island-comparison between 1993 and 1995

In the previous research in 1993, three of the authors found that some troops of wild Japanese macaques were provisionized by tourists, around the road in the western forest of Yakushima Island, south of Kyushu, Japan. Again in 1995, we conducted a research with the same methods in the same area. Here we reported the results of 1995 and compared them with those of 1993.We surveyed the area along the road of 19.2km, passing through the forest. We set eight stations along the road as survey units, with a mean length of 2.4km. Each station was surveyed for two days. Each of us walked slowly in the station and searched troops of monkeys. When the observer found the monkeys on or near the road, he or she began observation session for maximum of 30 minutes. At the end of observation session, the observer began to search another troop.During the observation session, we recorded the activities of monkeys and conducted“orange tests”. In the “orange tests”, we showed an orange to a monkey and recorded its response. If the monkey accessed to the orange, it was determined as provisionized.Percentages of provisionized monkeys were significantly different among the stations. However, no significant difference was found between the results of 1993 and 1995. Numbers of traffic passing through the road per day was 138.5, which was larger by 40 than in 1993. Among the traffic in 1995, at least 60% was due to tourists.The numbers of provisionized monkeys did not increased distinctively during the two years. However, numbers of tourists visiting the area apparently increased and the percentages of provisionized monkeys increased in some of the stations. Therefore, we should continue to monitor the provisionized monkeys and to make efforts to stop tourists from feeding monkeys.

Coming to America: Acclimation in macaque body structures and Bergmann’s rule

I analyzed somatometric measurements from subsets of the Texas and Oregon transplanted troops of Japanese macaques(Macaca fuscata) to reveal secular changes in body size and shape. Body weights of the Texas population (N = 59) are lower than those of the Oregon population(N = 49) and the founding population from Arashiyama. The adult weights of the Oregon population are significantly higher than the founding population from Mihara. There are significant differences in adult circumferential measures and in skinfolds, which are correlated with the increased weight of the Oregon macaques. The adult Texas macaques have longer limb segments in comparison with the adult Oregon troop members, while the latter have significantly longer heads and trunks. Examination of the developing morphological trends through regression analyses on the complete sample suggests distinctive growth patterns for each population. Members of the Texas population start with smaller initial measurements but hold a steeper growth pattern for limb segments, while the Oregon macaques start larger in most measures and show lower growth rates. I argue that these differences in both somatometry and growth patterns are related to the differing climatic conditions under which the translocated macaques have lived. This set of analyses supports the basic arguments for Bergmann’s rule and Allen’s rule.

Seniority Versus Age as Causes of Dominance in Social Groups

Seniority systems are fundamental organizing mechanisms of most social groups, but seniority is often confounded with chronological age. An analysis of male dominance orders in troops of Japanese and rhesus macaques showed that seniority within the macaque troops was clearly more predictive of dominance than was mere chronological age. Some quasiexperimental datafrom a sample of humans also revealed that seniority was more important than chronological age in determining employee layoff rankings. The Japanese macaque data camefrom Norikoshi and Koyama 's study of two wild butprovisionedtroops ofmonkeys, each containing 26adult males. The multiple regression of dominance rank on seniority and age produced standardized multiple regression coefficients of .65 and .35 for one troop, whereas thefiguresfor the other troop were .82 and .41, respectively. A secondary analysis of Hill's rhesus macaque data showed that seniority had a standardized multiple regression coefficient of .66, but the coerficientforage was only .16, supporting the Japanese macaque data. Finally, new data from a sample of humans showed a similar pattern When subjects were asked to establish a layoff ranking of hypothetical employees described by seniority and age, their rankings were determined primarily by seniority: The coefficients were. 75 and.10, respectively.

Frog- and lizard-eating behaviour of wild Japanese macaques in Yakushima, Japan

Frog- and lizard-eating and related behaviours were observed on eight occasions in two troops of wild Japanese macaques (Macaca fuscata yakui) in Yakushima, between March 1984 and April 1989. In each case, the first animal seen handling the prey was an adult. Juveniles showed interest in the prey, sniffed or mouthed it in three cases, and ate discarded parts of it in another. In the three cases where capture was observed, detection of the prey appeared to be fortuitous. Four monkeys ate leaves after eating meat. Those leaves identified were of species not commonly eaten. Though invertebrate-eating is common and widespread among Japanese macaques, the consumption of vertebrates is rare. The possibility that these behaviours represent a local tradition among the Yakushima macaques is discussed.