This research was supported in part by the Marine World Foundation. We would like to thank the Ma... more This research was supported in part by the Marine World Foundation. We would like to thank the Marine Research Center volunteer staff who assisted in data collection and entry. We also would like to thank Debbie Marrin, Terry Samansky and the Marine Mammal Department training staff at Six Flags Marine World who were responsible for the care and husbandry of the animals. Correspondence concerning this article should be addressed to Brenda McCowan, VMTRC
Social stability in group-living animals is an emergent property which arises from the interactio... more Social stability in group-living animals is an emergent property which arises from the interaction amongst multiple behavioral networks. However, pinpointing when a social group is at risk of collapse is difficult. We used a joint network modeling approach to examine the interdependencies between two behavioral networks, aggression and status signaling, from four stable and three unstable groups of rhesus macaques in order to identify characteristic patterns of network interdependence in stable groups that are readily distinguishable from unstable groups. Our results showed that the most prominent source of aggression-status network interdependence in stable social groups came from more frequent dyads than expected with opposite direction status-aggression (i.e. A threatens B and B signals acceptance of subordinate status). In contrast, unstable groups showed a decrease in opposite direction aggression-status dyads (but remained higher than expected) as well as more frequent than ex...
Journal of the American Association for Laboratory Animal Science : JAALAS, 2010
The purpose of this retrospective case-control study was to identify and assess biologically plau... more The purpose of this retrospective case-control study was to identify and assess biologically plausible variables that may predispose a captive rhesus macaque breeding colony to a matrilineal overthrow. Matrilineal overthrows are the result of members of multiple matrilines jointly attacking the highest-ranking matriline. Matrilineal overthrows in captive rhesus macaque colonies result in significant morbidity, mortality, and loss of genetic diversity. The following variables were investigated as potential determinants of overthrows: season, cage density, demographics, sex ratio, age of the alpha and beta animals, absence of the alpha and beta animals, pregnancy status of the alpha and beta females, number of adult females in the alpha matriline, recent changes in the male hierarchy, time since group formation, and number of adolescent males in the alpha matriline. Data were collected from January 1996 through January 2007. Univariate analysis indicated that absence of the alpha fema...
Journal of the American Association for Laboratory Animal Science : JAALAS, 2011
Primate facilities provide environmental enrichment to improve animal wellbeing, increase opportu... more Primate facilities provide environmental enrichment to improve animal wellbeing, increase opportunities for expression of species-typical behaviors, and decrease the occurrence of stereotypic behaviors. The current study assessed the efficacy of 3 types of foraging enrichment: puzzle balls, supertubes, and shakers. We assigned 48 rhesus macaques to 3 experimental groups, each of which received (after a 3-wk baseline observation period) 1 of the 3 enrichment devices intermittently for 3 wk. Observations were collected during 10-min sessions by using 1-0 sampling with 15-s intervals (480 h total). Observations were collected at the same 10 specified time points each week during the baseline period and after enrichment. Data were analyzed by using generalized linear mixed-effects modeling under the assumption that the underlying response followed a Poisson distribution. Foraging behavior increased significantly in all 3 groups and remained increased in some groups when enrichment was r...
Social isolation is a major risk factor for the development of depressive illness; yet, no practi... more Social isolation is a major risk factor for the development of depressive illness; yet, no practical nonhuman primate model is available for studying processes involved in this effect. In a first study, we noted that adult male rhesus monkeys housed individually indoors occasionally exhibited a hunched, depressive-like posture. Therefore, Study 2 investigated the occurrence of a hunched posture by adult males brought from outdoor social groups to indoor individual housing. We also scored two other behaviors-lying on the substrate and day time sleeping-that convey an impression of depression. During the first week of observation following individual housing, 18 of 26 adult males exhibited the hunched posture and 21 of 26 displayed at least one depressive-like behavior. Over 2 weeks, 23 of 26 males showed depressive-like behavior during a total of only 20 min observation. Further, the behavior during the first week was positively related to the level of initial response to a maternal ...
The Journal of the Acoustical Society of America, 2006
The goal of this research was to determine when harbor seal pup vocalizations become sufficiently... more The goal of this research was to determine when harbor seal pup vocalizations become sufficiently distinctive to allow individual recognition. A total of 4593 calls were analyzed from 15 captive pups. Nineteen were harsh, broadband, staccato calls used in an aggressive context. The rest were tonal “mother attraction calls,” having an inverted “v”- or “u”-shaped spectrogram with harmonics and a fundamental frequency around 200–600Hz. Calls were individually distinctive even in pups less than 2weeks old, suggesting that mothers may be able to recognize pup vocalizations at this early age. Classification rates from discriminant function analysis were generally comparable to those of other phocids and less than in otariids, supporting the theory that recognition is more highly developed in otariids. Significant differences were found between male and female pup calls, and there were significant interactions between pup sex and age. The results of this study should be interpreted with ca...
Considered signs of decreased welfare-abnormal behaviors such as self-injury and self-abuse among... more Considered signs of decreased welfare-abnormal behaviors such as self-injury and self-abuse among nonhuman primates housed in the laboratory-may put into question the validity and reliability of scientific research using these animals as models. Providing environmental enrichment decreases the incidence of some undesirable behaviors but is often unsuccessful at ameliorating the most severe types of abnormal behaviors. To prevent such behaviors from developing, it is important to identify risk factors that provide insight into the causes of certain abnormal behaviors. This study confirmed previous research identifying nursery rearing, single housing, and time spent in single housing as important risk factors. Results also indicate that the number of cage relocations affects the development of these behaviors. In addition, this study presents new data on comorbidity of several abnormal behaviors and discusses possible reasons for these patterns.
1. Although network analysis has drawn considerable attention as a promising tool for disease eco... more 1. Although network analysis has drawn considerable attention as a promising tool for disease ecology, empirical research has been hindered by limitations in detecting the occurrence of pathogen transmission (who transmitted to whom) within social networks. 2. Using a novel approach, we utilize the genetics of a diverse microbe, Escherichia coli, to infer where direct or indirect transmission has occurred and use these data to construct transmission networks for a wild giraffe population (Giraffe camelopardalis). Individuals were considered to be a part of the same transmission chain and were interlinked in the transmission network if they shared genetic subtypes of E. coli. 3. By using microbial genetics to quantify who transmits to whom independently from the behavioural data on who is in contact with whom, we were able to directly investigate how the structure of contact networks influences the structure of the transmission network. To distinguish between the effects of social and environmental contact on transmission dynamics, the transmission network was compared with two separate contact networks defined from the behavioural data: a social network based on association patterns, and a spatial network based on patterns of home-range overlap among individuals. 4. We found that links in the transmission network were more likely to occur between individuals that were strongly linked in the social network. Furthermore, individuals that had more numerous connections or that occupied 'bottleneck' positions in the social network tended to occupy similar positions in the transmission network. No similar correlations were observed between the spatial and transmission networks. This indicates that an individual's social network position is predictive of transmission network position, which has implications for identifying individuals that function as super-spreaders or transmission bottlenecks in the population. 5. These results emphasize the importance of association patterns in understanding transmission dynamics, even for environmentally transmitted microbes like E. coli. This study is the first to use microbial genetics to construct and analyse transmission networks in a wildlife population and highlights the potential utility of an approach integrating microbial genetics with network analysis.
What do the behavior of monkeys in captivity and the financial system have in common? The nodes i... more What do the behavior of monkeys in captivity and the financial system have in common? The nodes in such social systems relate to each other through multiple and keystone networks, not just one network. Each network in the system has its own topology, and the interactions among the system's networks change over time. In such systems, the lead into a crisis appears to be characterized by a decoupling of the networks from the keystone network. This decoupling can also be seen in the crumbling of the keystone's power structure toward a more horizontal hierarchy. This paper develops nonparametric methods for describing the joint model of the latent architecture of interconnected networks in order to describe this process of decoupling, and hence provide an early warning system of an impending crisis. * This paper was prepared for the 9 th International Institute of Forecasters' Workshop, Sept. 28-29, 2012, held at the Federal Reserve Bank of San Francisco. The views expressed herein are the sole responsibility of the authors, and should not be interpreted as reflecting the views of either the Federal Reserve Bank of San Francisco or the Board of Governors of the Federal Reserve System.
We show that dolphin whistle types tend to be used in specific behavioral contexts, which is cons... more We show that dolphin whistle types tend to be used in specific behavioral contexts, which is consistent with the hypothesis that dolphin whistle have some sort of "meaning". Besides, in some cases, it can be shown that the behavioral context in which a whistle tends to occur or not occur is shared by different individuals, which is consistent with the hypothesis that dolphins are communicating through whistles. Furthermore, we show that the number of behavioral contexts significantly associated with a certain whistle type tends to grow with the frequency of the whistle type, a pattern that is reminiscent of a law of word meanings stating, as a tendency, that the higher the frequency of a word, the higher its number of meanings. Our findings indicate that the presence of Zipf"s law in dolphin whistle types cannot be explained with enough detail by a simplistic die rolling experiment.
This study explored the role of learning in the development of chuck call recognition in squirrel... more This study explored the role of learning in the development of chuck call recognition in squirrel monkeys. We experimentally exposed subjects of four different age classes, under controlled conditions, to the chuck calls of genetically unrelated individuals of different social af nities. Using playback experimentation, we tested the hypothesis that subjects at different developmental stages respond preferentially to the chuck calls of geneticallyunrelated familiar social group companions when compared to those of unfamiliar individualsfrom outside of the social group. Results demonstrated that adults vocally respond preferentially to the chuck calls of familiar social group members. Subadults behaviorally respond preferentially to the chuck calls of close social associates within their social groups. Juveniles behaviorally responded more strongly to the playback of chuck calls arising from individuals within their colony when compared to the playback of 'silence.' Infants did not behaviorally or vocally respond preferentially to the chuck calls of close social associates or other social group members. These results demonstrate that learning plays a role in chuck call recognition in squirrel monkeys and may suggest that infants gradually learn to acoustically recognize social companions within their group.
It is increasingly recognized that association patterns of most gregarious animals are nonrandom.... more It is increasingly recognized that association patterns of most gregarious animals are nonrandom. However, nonrandom patterns can emerge in any population that exhibits spatial structure, even if individuals associate randomly. In species that lack clearly differentiated social relationships characteristic of socially complex mammals, space use patterns must be considered alongside association patterns in order to establish whether nonrandom association patterns are determined by underlying social structure or are merely an artifact of spatial structure. In this study, we simultaneously consider space use and association patterns for a wild population of reticulated giraffe. We examined whether the giraffe's flexible fission-fusion association patterns were embedded in higher levels of social organization. We identified multilevel social organization in which individuals were members of social cliques. Cliques were embedded in larger subcommunities, which in turn were embedded in communities. The frequency with which 2 individuals were observed together was positively correlated with the extent to which their home range overlapped, implying an underlying role of shared space use in determining association patterns. However, membership in cliques and subcommunities was relatively unrelated to space use patterns for males. For females, space use played a much larger role in determining multitiered social organization, which is consistent with a matrilineal-based society characterized by female philopatry. Although giraffe social interactions are highly fluid in nature, it is apparent that association patterns in giraffe are not the result of random fission-fusion events but are embedded within a structured social network characterized by multiple levels of organization.
Laboratory and zoo housed non-human primates sometimes exhibit abnormal behaviors that are though... more Laboratory and zoo housed non-human primates sometimes exhibit abnormal behaviors that are thought to reflect reduced wellbeing. Previous research attempted to identify risk factors to aid in the prevention and treatment of these behaviors, and focused on demographic (e.g. sex or age) and experience-related (e.g. single housing or nursery rearing) factors. However, not all animals that display abnormal behavior possess these risk factors and some individuals that possess a risk factor do not show behavioral abnormalities. We hypothesized that other aspects of early experience and individual characteristics might identify animals that were more likely to display one specific abnormal behavior, motor stereotypy (MS). Using logistic regression we explored the influence of early rearing (involving four different types of rearing conditions), and variation in temperament, on likelihood of displaying MS while controlling for previously identified risk factors. Analyses indicated that having a greater proportion of life lived indoors, a greater proportion of life-indoors singly-housed, and a greater number of anesthesias and blood draws significantly increased the risk of displaying MS (P < 0.001). Rearing condition failed to independently predict the display of MS; however significant interactions indicated that single housing had a greater impact on risk for indoor-reared animals versus outdoor-reared animals, and for indoor mother-reared animals versus nursery-reared animals. There were no main effects of temperament, although interactions with rearing were evident: scoring high on Gentle or Nervous was a risk factor for indoor-reared animals but not outdoor-reared animals. The final model accounted for approximately 69.3 % of the variance in the display of MS, and correctly classified 90.6% of animals. These results indicate that previously identified risk factors may impact animals differently depending on the individual's early rearing condition. These results are also the first in non-human primates to demonstrate that individual difference factors, like temperament, could be additional tools to identify animals at highest risk for motor stereotypy.
Rhesus macaques, like many other primates, live in stable, multi-male multi-female groups in whic... more Rhesus macaques, like many other primates, live in stable, multi-male multi-female groups in which adult females typically outnumber adult males. The number of males in multi-male/multifemale groups is most commonly discussed in terms of mate competition, where the sex ratio is a function of an adult male's ability to monopolize a group of females. However, the relationship between sex ratio and group stability is unclear because the presence of many males may either reduce stability by increasing mate competition or may improve stability if adult males are key conflict managers. We investigated the relationship between sex ratio, male intervention behavior, and trauma in seven groups of captive rhesus macaques. Our results show that high-ranking adult males intervene twice as frequently as adult females (P<0.0001) and are about twice as successful (P<0.0001). Furthermore, the type of adult males present in the group affects the relationship between intervention behavior and rate of traumas: males must be unrelated to the highest-ranking matrilines. Groups with a lower ratio of females per male unrelated to the alpha and beta matrilines had better intervention success (P<0.04) and fewer traumas requiring veterinary care (P=0.003). We conclude that conflict management behavior by adult males, particularly those unrelated to the highest-ranking matrilines, is the mechanism by which sex ratio influences the frequency of traumas, and thus group stability. We therefore suggest that monitoring and managing the sex ratio of captive primate groups is one of many measurements to predict group stability.
This research was supported in part by the Marine World Foundation. We would like to thank the Ma... more This research was supported in part by the Marine World Foundation. We would like to thank the Marine Research Center volunteer staff who assisted in data collection and entry. We also would like to thank Debbie Marrin, Terry Samansky and the Marine Mammal Department training staff at Six Flags Marine World who were responsible for the care and husbandry of the animals. Correspondence concerning this article should be addressed to Brenda McCowan, VMTRC
Social stability in group-living animals is an emergent property which arises from the interactio... more Social stability in group-living animals is an emergent property which arises from the interaction amongst multiple behavioral networks. However, pinpointing when a social group is at risk of collapse is difficult. We used a joint network modeling approach to examine the interdependencies between two behavioral networks, aggression and status signaling, from four stable and three unstable groups of rhesus macaques in order to identify characteristic patterns of network interdependence in stable groups that are readily distinguishable from unstable groups. Our results showed that the most prominent source of aggression-status network interdependence in stable social groups came from more frequent dyads than expected with opposite direction status-aggression (i.e. A threatens B and B signals acceptance of subordinate status). In contrast, unstable groups showed a decrease in opposite direction aggression-status dyads (but remained higher than expected) as well as more frequent than ex...
Journal of the American Association for Laboratory Animal Science : JAALAS, 2010
The purpose of this retrospective case-control study was to identify and assess biologically plau... more The purpose of this retrospective case-control study was to identify and assess biologically plausible variables that may predispose a captive rhesus macaque breeding colony to a matrilineal overthrow. Matrilineal overthrows are the result of members of multiple matrilines jointly attacking the highest-ranking matriline. Matrilineal overthrows in captive rhesus macaque colonies result in significant morbidity, mortality, and loss of genetic diversity. The following variables were investigated as potential determinants of overthrows: season, cage density, demographics, sex ratio, age of the alpha and beta animals, absence of the alpha and beta animals, pregnancy status of the alpha and beta females, number of adult females in the alpha matriline, recent changes in the male hierarchy, time since group formation, and number of adolescent males in the alpha matriline. Data were collected from January 1996 through January 2007. Univariate analysis indicated that absence of the alpha fema...
Journal of the American Association for Laboratory Animal Science : JAALAS, 2011
Primate facilities provide environmental enrichment to improve animal wellbeing, increase opportu... more Primate facilities provide environmental enrichment to improve animal wellbeing, increase opportunities for expression of species-typical behaviors, and decrease the occurrence of stereotypic behaviors. The current study assessed the efficacy of 3 types of foraging enrichment: puzzle balls, supertubes, and shakers. We assigned 48 rhesus macaques to 3 experimental groups, each of which received (after a 3-wk baseline observation period) 1 of the 3 enrichment devices intermittently for 3 wk. Observations were collected during 10-min sessions by using 1-0 sampling with 15-s intervals (480 h total). Observations were collected at the same 10 specified time points each week during the baseline period and after enrichment. Data were analyzed by using generalized linear mixed-effects modeling under the assumption that the underlying response followed a Poisson distribution. Foraging behavior increased significantly in all 3 groups and remained increased in some groups when enrichment was r...
Social isolation is a major risk factor for the development of depressive illness; yet, no practi... more Social isolation is a major risk factor for the development of depressive illness; yet, no practical nonhuman primate model is available for studying processes involved in this effect. In a first study, we noted that adult male rhesus monkeys housed individually indoors occasionally exhibited a hunched, depressive-like posture. Therefore, Study 2 investigated the occurrence of a hunched posture by adult males brought from outdoor social groups to indoor individual housing. We also scored two other behaviors-lying on the substrate and day time sleeping-that convey an impression of depression. During the first week of observation following individual housing, 18 of 26 adult males exhibited the hunched posture and 21 of 26 displayed at least one depressive-like behavior. Over 2 weeks, 23 of 26 males showed depressive-like behavior during a total of only 20 min observation. Further, the behavior during the first week was positively related to the level of initial response to a maternal ...
The Journal of the Acoustical Society of America, 2006
The goal of this research was to determine when harbor seal pup vocalizations become sufficiently... more The goal of this research was to determine when harbor seal pup vocalizations become sufficiently distinctive to allow individual recognition. A total of 4593 calls were analyzed from 15 captive pups. Nineteen were harsh, broadband, staccato calls used in an aggressive context. The rest were tonal “mother attraction calls,” having an inverted “v”- or “u”-shaped spectrogram with harmonics and a fundamental frequency around 200–600Hz. Calls were individually distinctive even in pups less than 2weeks old, suggesting that mothers may be able to recognize pup vocalizations at this early age. Classification rates from discriminant function analysis were generally comparable to those of other phocids and less than in otariids, supporting the theory that recognition is more highly developed in otariids. Significant differences were found between male and female pup calls, and there were significant interactions between pup sex and age. The results of this study should be interpreted with ca...
Considered signs of decreased welfare-abnormal behaviors such as self-injury and self-abuse among... more Considered signs of decreased welfare-abnormal behaviors such as self-injury and self-abuse among nonhuman primates housed in the laboratory-may put into question the validity and reliability of scientific research using these animals as models. Providing environmental enrichment decreases the incidence of some undesirable behaviors but is often unsuccessful at ameliorating the most severe types of abnormal behaviors. To prevent such behaviors from developing, it is important to identify risk factors that provide insight into the causes of certain abnormal behaviors. This study confirmed previous research identifying nursery rearing, single housing, and time spent in single housing as important risk factors. Results also indicate that the number of cage relocations affects the development of these behaviors. In addition, this study presents new data on comorbidity of several abnormal behaviors and discusses possible reasons for these patterns.
1. Although network analysis has drawn considerable attention as a promising tool for disease eco... more 1. Although network analysis has drawn considerable attention as a promising tool for disease ecology, empirical research has been hindered by limitations in detecting the occurrence of pathogen transmission (who transmitted to whom) within social networks. 2. Using a novel approach, we utilize the genetics of a diverse microbe, Escherichia coli, to infer where direct or indirect transmission has occurred and use these data to construct transmission networks for a wild giraffe population (Giraffe camelopardalis). Individuals were considered to be a part of the same transmission chain and were interlinked in the transmission network if they shared genetic subtypes of E. coli. 3. By using microbial genetics to quantify who transmits to whom independently from the behavioural data on who is in contact with whom, we were able to directly investigate how the structure of contact networks influences the structure of the transmission network. To distinguish between the effects of social and environmental contact on transmission dynamics, the transmission network was compared with two separate contact networks defined from the behavioural data: a social network based on association patterns, and a spatial network based on patterns of home-range overlap among individuals. 4. We found that links in the transmission network were more likely to occur between individuals that were strongly linked in the social network. Furthermore, individuals that had more numerous connections or that occupied 'bottleneck' positions in the social network tended to occupy similar positions in the transmission network. No similar correlations were observed between the spatial and transmission networks. This indicates that an individual's social network position is predictive of transmission network position, which has implications for identifying individuals that function as super-spreaders or transmission bottlenecks in the population. 5. These results emphasize the importance of association patterns in understanding transmission dynamics, even for environmentally transmitted microbes like E. coli. This study is the first to use microbial genetics to construct and analyse transmission networks in a wildlife population and highlights the potential utility of an approach integrating microbial genetics with network analysis.
What do the behavior of monkeys in captivity and the financial system have in common? The nodes i... more What do the behavior of monkeys in captivity and the financial system have in common? The nodes in such social systems relate to each other through multiple and keystone networks, not just one network. Each network in the system has its own topology, and the interactions among the system's networks change over time. In such systems, the lead into a crisis appears to be characterized by a decoupling of the networks from the keystone network. This decoupling can also be seen in the crumbling of the keystone's power structure toward a more horizontal hierarchy. This paper develops nonparametric methods for describing the joint model of the latent architecture of interconnected networks in order to describe this process of decoupling, and hence provide an early warning system of an impending crisis. * This paper was prepared for the 9 th International Institute of Forecasters' Workshop, Sept. 28-29, 2012, held at the Federal Reserve Bank of San Francisco. The views expressed herein are the sole responsibility of the authors, and should not be interpreted as reflecting the views of either the Federal Reserve Bank of San Francisco or the Board of Governors of the Federal Reserve System.
We show that dolphin whistle types tend to be used in specific behavioral contexts, which is cons... more We show that dolphin whistle types tend to be used in specific behavioral contexts, which is consistent with the hypothesis that dolphin whistle have some sort of "meaning". Besides, in some cases, it can be shown that the behavioral context in which a whistle tends to occur or not occur is shared by different individuals, which is consistent with the hypothesis that dolphins are communicating through whistles. Furthermore, we show that the number of behavioral contexts significantly associated with a certain whistle type tends to grow with the frequency of the whistle type, a pattern that is reminiscent of a law of word meanings stating, as a tendency, that the higher the frequency of a word, the higher its number of meanings. Our findings indicate that the presence of Zipf"s law in dolphin whistle types cannot be explained with enough detail by a simplistic die rolling experiment.
This study explored the role of learning in the development of chuck call recognition in squirrel... more This study explored the role of learning in the development of chuck call recognition in squirrel monkeys. We experimentally exposed subjects of four different age classes, under controlled conditions, to the chuck calls of genetically unrelated individuals of different social af nities. Using playback experimentation, we tested the hypothesis that subjects at different developmental stages respond preferentially to the chuck calls of geneticallyunrelated familiar social group companions when compared to those of unfamiliar individualsfrom outside of the social group. Results demonstrated that adults vocally respond preferentially to the chuck calls of familiar social group members. Subadults behaviorally respond preferentially to the chuck calls of close social associates within their social groups. Juveniles behaviorally responded more strongly to the playback of chuck calls arising from individuals within their colony when compared to the playback of 'silence.' Infants did not behaviorally or vocally respond preferentially to the chuck calls of close social associates or other social group members. These results demonstrate that learning plays a role in chuck call recognition in squirrel monkeys and may suggest that infants gradually learn to acoustically recognize social companions within their group.
It is increasingly recognized that association patterns of most gregarious animals are nonrandom.... more It is increasingly recognized that association patterns of most gregarious animals are nonrandom. However, nonrandom patterns can emerge in any population that exhibits spatial structure, even if individuals associate randomly. In species that lack clearly differentiated social relationships characteristic of socially complex mammals, space use patterns must be considered alongside association patterns in order to establish whether nonrandom association patterns are determined by underlying social structure or are merely an artifact of spatial structure. In this study, we simultaneously consider space use and association patterns for a wild population of reticulated giraffe. We examined whether the giraffe's flexible fission-fusion association patterns were embedded in higher levels of social organization. We identified multilevel social organization in which individuals were members of social cliques. Cliques were embedded in larger subcommunities, which in turn were embedded in communities. The frequency with which 2 individuals were observed together was positively correlated with the extent to which their home range overlapped, implying an underlying role of shared space use in determining association patterns. However, membership in cliques and subcommunities was relatively unrelated to space use patterns for males. For females, space use played a much larger role in determining multitiered social organization, which is consistent with a matrilineal-based society characterized by female philopatry. Although giraffe social interactions are highly fluid in nature, it is apparent that association patterns in giraffe are not the result of random fission-fusion events but are embedded within a structured social network characterized by multiple levels of organization.
Laboratory and zoo housed non-human primates sometimes exhibit abnormal behaviors that are though... more Laboratory and zoo housed non-human primates sometimes exhibit abnormal behaviors that are thought to reflect reduced wellbeing. Previous research attempted to identify risk factors to aid in the prevention and treatment of these behaviors, and focused on demographic (e.g. sex or age) and experience-related (e.g. single housing or nursery rearing) factors. However, not all animals that display abnormal behavior possess these risk factors and some individuals that possess a risk factor do not show behavioral abnormalities. We hypothesized that other aspects of early experience and individual characteristics might identify animals that were more likely to display one specific abnormal behavior, motor stereotypy (MS). Using logistic regression we explored the influence of early rearing (involving four different types of rearing conditions), and variation in temperament, on likelihood of displaying MS while controlling for previously identified risk factors. Analyses indicated that having a greater proportion of life lived indoors, a greater proportion of life-indoors singly-housed, and a greater number of anesthesias and blood draws significantly increased the risk of displaying MS (P < 0.001). Rearing condition failed to independently predict the display of MS; however significant interactions indicated that single housing had a greater impact on risk for indoor-reared animals versus outdoor-reared animals, and for indoor mother-reared animals versus nursery-reared animals. There were no main effects of temperament, although interactions with rearing were evident: scoring high on Gentle or Nervous was a risk factor for indoor-reared animals but not outdoor-reared animals. The final model accounted for approximately 69.3 % of the variance in the display of MS, and correctly classified 90.6% of animals. These results indicate that previously identified risk factors may impact animals differently depending on the individual's early rearing condition. These results are also the first in non-human primates to demonstrate that individual difference factors, like temperament, could be additional tools to identify animals at highest risk for motor stereotypy.
Rhesus macaques, like many other primates, live in stable, multi-male multi-female groups in whic... more Rhesus macaques, like many other primates, live in stable, multi-male multi-female groups in which adult females typically outnumber adult males. The number of males in multi-male/multifemale groups is most commonly discussed in terms of mate competition, where the sex ratio is a function of an adult male's ability to monopolize a group of females. However, the relationship between sex ratio and group stability is unclear because the presence of many males may either reduce stability by increasing mate competition or may improve stability if adult males are key conflict managers. We investigated the relationship between sex ratio, male intervention behavior, and trauma in seven groups of captive rhesus macaques. Our results show that high-ranking adult males intervene twice as frequently as adult females (P<0.0001) and are about twice as successful (P<0.0001). Furthermore, the type of adult males present in the group affects the relationship between intervention behavior and rate of traumas: males must be unrelated to the highest-ranking matrilines. Groups with a lower ratio of females per male unrelated to the alpha and beta matrilines had better intervention success (P<0.04) and fewer traumas requiring veterinary care (P=0.003). We conclude that conflict management behavior by adult males, particularly those unrelated to the highest-ranking matrilines, is the mechanism by which sex ratio influences the frequency of traumas, and thus group stability. We therefore suggest that monitoring and managing the sex ratio of captive primate groups is one of many measurements to predict group stability.
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Papers by Brenda McCowan