Groups Of Meerkats Research Articles

Mapping vocal interactions in space and time differentiates signal broadcast versus signal exchange in meerkat groups.

Animal vocal communication research traditionally focuses on acoustic and contextual features of calls, yet substantial information is also contained in response selectivity and timing during vocalization events. By examining the spatiotemporal structure of vocal interactions, we can distinguish between 'broadcast' and 'exchange' signalling modes, with the former potentially serving to transmit signallers' general state and the latter reflecting more interactive signalling behaviour. Here, we tracked the movements and vocalizations of wild meerkat (Suricata suricatta) groups simultaneously using collars to explore this distinction. We found evidence that close calls (used for maintaining group cohesion) are given as signal exchanges. They are typically given in temporally structured call-response sequences and are also strongly affected by the social environment, with individuals calling more when they have more neighbours and juveniles responding more to adults than the reverse. In contrast, short note calls appear mainly in sequences produced by single individuals and show little dependence on social surroundings, suggesting a broadcast signalling mode. Despite these differences, both call categories show similar clustering in space and time at a group level. Our results highlight how the fine-scale structure of vocal interactions can give important insights into the usage and function of signals in social groups. This article is part of the theme issue 'The power of sound: unravelling how acoustic communication shapes group dynamics.'

Disentangling influence over group speed and direction reveals multiple patterns of influence in moving meerkat groups

Animals that travel together in groups must constantly come to consensus about both the direction and speed of movement, often simultaneously. Contributions to collective decisions may vary among group members, yet inferring who has influence over group decisions is challenging, largely due to the multifaceted nature of influence. Here we collected high-resolution GPS data from five habituated meerkat groups in their natural habitat during foraging and developed a method to quantify individual influence over both group direction and speed. We find that individual influence over direction and speed are correlated, but also exhibit substantial variation. Comparing patterns across social statuses reveals that dominant females have higher influence than other individuals over both group direction and speed. Individuals with high influence also tend to spend more time in the front of the group. We discuss our results in light of meerkat life-history and current literature on influence during group movement. Our method provides a general approach which can be applied to disentangle individual influence over group direction and speed in a wide range of species with cohesive movement, emphasizing the importance of integrating multiple lines of inquiry when inferring influence in moving animal groups.

Dispersal Decreases Survival but Increases Reproductive Opportunities for Subordinates in a Cooperative Breeder.

AbstractIn most socially structured populations, the formation of new groups depends on the survival and reproduction of dispersing individuals. Quantifying vital rates in dispersers, however, is difficult because of the logistic challenges of following wide-ranging animals. Here, using data from free-ranging meerkats (Suricata suricatta), we estimate survival and reproduction of dispersing females and compare these estimates to data for established residents. Meerkat groups consist of a dominant pair and several subordinate helpers. Female helpers are evicted from their resident groups by the dominant female, allowing her to monopolize reproduction, and evicted females may form small dispersing coalitions. We show that, as in established resident groups, one female is behaviorally dominant in parties of dispersing females. During dispersal and the first 4 months after new group formation, survival is lower for all females compared with established resident groups. At the same time, subordinates in disperser groups have higher birth rates than those in established groups, which rarely breed successfully. This may partly offset the survival costs of dispersal to subordinate females. Further studies of dispersal based on direct observation of dispersing animals are needed to explore the costs and benefits of dispersal in species with contrasting breeding systems.

Sentinel behavior in captive meerkats (Suricata suricatta).

The social and cooperative behavior of meerkats (Suricata suricatta), specifically their sentinel behavior, has been intensively studied in free-ranging populations. This study focuses on whether guarding in captive meerkats exhibits a pattern similar to that described for wild groups. Sentinel behavior in captivity has been somewhat neglected because predation is usually not a critical factor. Nonetheless, observations in captivity might reveal whether individual or group experience influences this specific behavior pattern. We observed three captive meerkat groups (in outdoor as well as indoor enclosures) and analyzed the duration of guarding sequences, the number of established guards, the guard posture, and the individual guard positions. We also conducted playback experiments to investigate the reaction of the sentinel and the group to bird calls (songbird vs. predatory bird species). The results demonstrated that captive groups behave much the same as wild groups. Certain individuals performed the guard job more often than other group members. Accordingly, the "super sentinels"observed in the wild also exist in captive groups. Playbacks showed that the sentinels reacted more strongly to the calls of predatory bird species, indicating that captive meerkats are able to categorize bird calls. We also documented major differences in behavioral responses to the calls of specific predatory bird species. Our observations underline that sentinel behavior is probably a combination of an innate, imprinted pattern that is further affected by the experience. Future studies might further investigate this influence of experience, beyond innate behavior, on the group-specific sentinel behavior pattern in captive meerkats.

Does the social network structure of wild animal populations differ from that of animals in captivity?

The social behaviour of wild animals living in groups leads to social networks with structures that produce group-level effects and position individuals within them with differential consequences for an individual’s fitness. Social dynamics in captivity can differ greatly from those in wild conspecifics given the different constraints on social organization in wild populations, e.g. group size, predation pressure, distribution of resources (food, mates), which are all regulated by human carers in captive populations. The social networks of animals in zoos is expected to differ from those of free-living conspecifics. While many studies have described the social networks of a wide diversity of wild and captive animals, none has directly compared the networks of multiple groups of a single species both in the wild and in captivity. Meerkats, Suricata suricatta, are an excellent species to compare the social networks of wild and captive groups. We replicated the methods of Madden et al. (2009, 2011), who studied eight groups in the wild, in fifteen captive groups. We tested how network structures and individual positions in grooming, foraging competition and dominance networks differed between wild and captive groups. Groups of wild and captive meerkats differed in various aspects of their social network structure. Differences in the network may be due to individuals occupying different network positions and the difference in the number and strength of their connections to other individuals. This distinct way of interacting and associating could be a result of group specific attributes, such as group size, and/or the attributes of the donor and recipient, including sex, status or age. Critically, the differences may be explained by the dissimilar living environment that each encounters.

How consistently do personality attributes relate to an individual’s position within a social network: a comparison across groups of captive meerkats

The social network structure of a group arises from the patterns of association of its constituent members, which in turn originates from behaviors and preferences of those individuals. Consequently, an individual’s position in their social environment is commonly related to their own attributes. However, most studies that report such relationships are limited to single or very small numbers of groups. I consider one set of attributes suggested to influence network structure, namely personality type, and observed 15 groups of captive meerkats Suricata suricatta. Thus, I could assess whether the relationship between individual attributes and patterns of association and network position persisted across groups. Principal component analysis of behavior, within the 15 groups, revealed two personality dimensions: friendliness and aggressiveness. For a subset of five groups, only friendliness was consistent over 1 year. I found little evidence that they were universally good predictors of social network structure or individual positions within networks. Individuals with high friendliness scores were more central in networks of foraging competitions. There was no evidence that meerkats preferentially associated with or avoid others based on each of their personality scores. Alternatively, and contrary to much-published work, it may not be possible to generalize relationships between individual attributes and network position or overall network structure. This may be because social environments emerge from a complex interplay between individual attributes and social interactions, and thus, the role of these elements along with the physical environment in which they live in shaping network structures and personality is challenging to disentangle. Animal personalities and animal social network structures are increasingly recognized as significant components in animal behavior and welfare. Here, I explore personality in the context of social networks in different captive groups of meerkats. These types of studies are uncommon probably because collecting detailed interaction data from multiple known individuals in multiple groups is time-consuming and because groups are often highly variable in composition and ecological context. When I did consider the social networks and individual attributes of members of 15 groups, I found little evidence that an individual’s personality scores consistently explained either their network position or patterns of association across all groups. Individuals in the wild, with different personality profiles, may adjust their network assortment to balance their costs and benefits and shift their environmental pressures. In a captive environment, such characteristics can vary and therefore social associations may be expressed differently from their wild counterparts.

Intergroup aggression in meerkats.

Violent conflicts between groups have been observed among many species of group living mammals and can have important fitness consequences, with individuals being injured or killed and with losing groups surrendering territory. Here, we explore between-group conflict among meerkats (Suricata suricatta), a highly social and cooperatively breeding mongoose. We show that interactions between meerkat groups are frequently aggressive and sometimes escalate to fighting and lethal violence and that these interactions have consequences for group territories, with losing groups moving to sleeping burrows closer to the centre of their territories following an intergroup interaction and with winning groups moving further away. We find that larger groups and groups with pups are significantly more likely to win contests, but that the location of the contest, adult sex ratio, and mean within-group genetic relatedness do not predict contest outcome. Our results suggest that intergroup competition may be a major selective force among meerkats, reinforcing the success of large groups and increasing the vulnerability of small groups to extinction. The presence of both within-group cooperation and between-group hostility in meerkats make them a valuable point of comparison in attempts to understand the ecological and evolutionary roots of human warfare.

Burrow usage patterns and decision-making in meerkat groups

Abstract Choosing suitable sleeping sites is a common challenge faced by animals across a range of taxa, with important implications for the space usage patterns of individuals, groups, and ultimately populations. A range of factors may affect these decisions, including access to resources nearby, shelter from the elements, safety from predators, territorial defense, and protection of offspring. We investigated the factors driving patterns of sleeping site use in wild Kalahari meerkats (Suricata suricatta), a cooperatively breeding, territorial mongoose species that forages on scattered resources and makes use of multiple sleeping sites (burrows). We found that meerkat groups used some burrows much more often than others. In particular, large burrows near the center of the territory were used more often than small and peripheral burrows, and groups became even more biased toward central burrows when rearing pups. Meerkats also used their sleeping burrows in a nonrandom order. When they changed sleeping burrows, they moved disproportionately to nearby burrows but did not always select the closest burrow. Burrow decisions also reflected responses to short-term conditions: rates of switching burrows increased after encounters with predators and when resources were depleted, whereas group splits were associated with a reduced probability of switching. The group’s dominant female appeared to have disproportionate influence over burrow decisions, as groups were more likely to switch burrows when her foraging success was low. Our results link behavioral and movement ecology to show that a multitude of environmental and social factors shape daily group decisions of where to spend the night.

Animal Communication: Chit-Chat in Meerkats

Coordinated behaviors are the hallmark of animal societies. General mechanisms for the emergence of social group dynamics are still unknown. New research suggests that a vocal feedback loop explains the appearance of coordinated vocal exchanges in large groups of meerkats.

Spatial structure of foraging meerkat groups is affected by both social and ecological factors

Group-living animals need to trade off the benefits and the costs of close proximity to conspecifics. Benefits can be increased, and costs reduced by preferentially choosing specific locations within a group best adjusted to an individual’s needs or by associating with specific group members and/or avoiding others. We investigated the spatial structure of meerkat (Suricata suricatta) groups and whether it was shaped by social factors such as affiliation or aggression among group members, predation risk, foraging success, or a mix of these different factors. Using social network analyses, based on spatial networks, we found associations between the dominant pair, among males and among same aged individuals, and dis-assortment by sex only in one to two of the six groups. In addition, the structure of meerkat groups was highly variable, as individual strength within the calculated networks was not repeatable over time. Meerkats seemed to adjust their location to their physical environment, as dominant individuals were located further toward the front of the group, where foraging success is likely higher and young individuals located further toward the back of the group, where they can benefit most from the vigilance effort of their conspecifics. We conclude that meerkat groups display a dynamic spatial structure depending on both the current social and physical environmental. Group-living animals can achieve greater benefits from close association with conspecifics by choosing specific locations within a group or associating with specific group members and/or avoiding others. A considerable body of work has examined how differences in predation risk or foraging success affect the relative location of individuals within a group. Several studies investigated the association between individuals, in order to draw conclusions on the social structure. However, it is important to disentangle the impact of all of these different aspects on the spatial structure of a group. Here, we provide evidence that both the social and physical environment is important for the spatial assortment of meerkats, a social mongoose foraging in cohesive groups.

A non‐invasive method for sampling the body odour of mammals

Abstract Olfaction is a central aspect of mammalian communication, providing information about individual attributes such as identity, sex, group membership or genetic quality. Yet, the chemical underpinnings of olfactory cues remain little understood, one of the reasons being the difficulty in obtaining high quality samples for chemical analysis. In this study, we adjusted and evaluated the use of thermal desorption (TD) tubes, commonly used in plant metabolomic and environmental studies, for non‐invasive sampling of mammalian body odour. We obtained chemical profiles of meerkat (Suricata suricatta) body odour samples, using TD tubes analysed with gas chromatography–mass spectrometry. TD tubes captured a wide range of volatile and semi‐volatile organic compounds, including compounds likely originating from the target animals. Adjustment of sampling parameters (distance, volume, flow rate, interruption of sampling) to increase the feasibility for a non‐invasive application yielded samples of adequate quality. However, to minimize the variability between samples, sampling parameters should be kept constant and samples should be collected when no conspecifics are close‐by. The method was sensitive enough to pick up population differences in the chemical profiles of two captive groups of meerkats, demonstrating its applicability to biological questions. With sufficiently habituated animals, the method is applicable non‐invasively, allowing short‐ and long‐term studies on a wide range of questions, including e.g. chemical signatures of kinship, diet, individual health or reproductive state.

Group size and visitor numbers predict faecal glucocorticoid concentrations in zoo meerkats.

Measures of physiological stress in zoo animals can give important insights into how they are affected by aspects of their captive environment. We analysed the factors influencing variation in glucocorticoid metabolites in faeces (fGCs) from zoo meerkats as a proxy for blood cortisol concentration, high levels of which are associated with a stress response. Levels of fGCs in captive meerkats declined with increasing group size. In the wild, very small groups of meerkats are at a higher risk of predation, while in larger groups, there is increased competition for resources. Indeed, group sizes in captivity resemble those seen in unstable coalitions in the wild, which may represent a stressful condition and predispose meerkats to chronic stress, even in the absence of natural predators. Individuals in large enclosures showed lower levels of stress, but meerkat density had no effect on the stress measures. In contrast with data from wild meerkats, neither sex, age nor dominance status predicted stress levels, which may reflect less food stress owing to more equal access to resources in captivity versus wild. The median number of visitors at the enclosure was positively correlated with fGC concentrations on the following day, with variation in the visitor numbers having the opposite effect. Our results are consistent with the hypothesis that there is an optimum group size which minimizes physiological stress in meerkats, and that zoo meerkats at most risk of physiological stress are those kept in small groups and small enclosures and are exposed to consistently high numbers of visitors.

Use of deslorelin implants for contraception in slender tailed meerkats (Suricata suricatta)

Deslorelin acetate implants are advocated for contraception in many mammalian species, including meerkats (Suricata suricatta), but little objective data exists on efficacy of this method. This study followed two groups...

Suppressing subordinate reproduction provides benefits to dominants in cooperative societies of meerkats.

In many animal societies, a small proportion of dominant females monopolize reproduction by actively suppressing subordinates. Theory assumes that this is because subordinate reproduction depresses the fitness of dominants, yet the effect of subordinate reproduction on dominant behaviour and reproductive success has never been directly assessed. Here, we describe the consequences of experimentally preventing subordinate breeding in 12 groups of wild meerkats (Suricata suricatta) for three breeding attempts, using contraceptive injections. When subordinates are prevented from breeding, dominants are less aggressive towards subordinates and evict them less often, leading to a higher ratio of helpers to dependent pups, and increased provisioning of the dominant’s pups by subordinate females. When subordinate breeding is suppressed, dominants also show improved foraging efficiency, gain more weight during pregnancy and produce heavier pups, which grow faster. These results confirm the benefits of suppression to dominants, and help explain the evolution of singular breeding in vertebrate societies.

Why Did the Meerkat Cross the Road? Flexible Adaptation of Phylogenetically-Old Behavioural Strategies to Modern-Day Threats

Risk-sensitive adaptive spatial organisation during group movement has been shown to efficiently minimise the risks associated with external ecological threats. Whether animals can draw on such behaviours when confronted with man-made threats is generally less clear. We studied road-crossing in a wild, but habituated, population of meerkats living in the Kalahari Desert, South Africa. We found that dominant females, the core member in meerkat social systems, led groups to the road significantly more often than subordinates, yet were consistently less likely to cross first. Our results suggest that a reshuffling occurs in progression order when meerkat groups reach the road. By employing a simple model of collective movement, we have shown that risk aversion alone may be sufficient to explain this reshuffling, but that the risk aversion of dominant females toward road crossing is significantly higher than that of subordinates. It seems that by not crossing first, dominant females avoid occupying the most risky, exposed locations, such as at the front of the group – a potential selfish strategy that also promotes the long-term stability and hence reproductive output of their family groups. We argue that our findings support the idea that animals can flexibly apply phylogenetically-old behavioural strategies to deal with emerging modern-day problems.

Identification of Learning Mechanisms in a Wild Meerkat Population

Vigorous debates as to the evolutionary origins of culture remain unresolved due to an absence of methods for identifying learning mechanisms in natural populations. While laboratory experiments on captive animals have revealed evidence for a number of mechanisms, these may not necessarily reflect the processes typically operating in nature. We developed a novel method that allows social and asocial learning mechanisms to be determined in animal groups from the patterns of interaction with, and solving of, a task. We deployed it to analyse learning in groups of wild meerkats (Suricata suricatta) presented with a novel foraging apparatus. We identify nine separate learning processes underlying the meerkats’ foraging behaviour, in each case precisely quantifying their strength and duration, including local enhancement, emulation, and a hitherto unrecognized form of social learning, which we term ‘observational perseverance’. Our analysis suggests a key factor underlying the stability of behavioural traditions is a high ratio of specific to generalized social learning effects. The approach has widespread potential as an ecologically valid tool to investigate learning mechanisms in natural groups of animals, including humans.

Innovative problem solving in wild meerkats

Behavioural innovations may have far-reaching evolutionary and ecological consequences, allowing individuals to obtain new resources and cope with environmental change. However, as innovations are rarely observed in nature, their emergence is poorly understood. What drives individuals to innovate, and what psychological mechanisms allow them to do so? We used three novel food extraction tasks to address these questions in groups of wild meerkats, Suricata suricatta. Innovatory tendencies were unrelated to body condition and foraging success, but were affected by age, rank and sex. Juvenile individuals were most likely to interact with tasks, but seldom solved them, perhaps owing to their small size or lack of dexterity. Instead, adult subordinates made up the bulk of the innovators. In cooperatively breeding societies, the inability of subordinate helpers to compete physically with dominant breeders may drive them to seek out solutions to novel problems. Most innovators were males, which, as the dispersing sex, may be particularly prone to solve novel problems, and innovators virtually always persisted longer than other group members when interacting with tasks. Most successful individuals solved tasks more than once, and learned to inhibit ineffective prepotent responses across successive presentations of the same task. They did not learn to manipulate functional parts of the apparatus more efficiently, however, nor did they extract general rules allowing them to solve novel tasks faster. Contrary to recent suggestions that innovation may be cognitively demanding, these results suggest that simple, conserved learning processes and dogged perseverance may suffice to generate solutions to novel problems.

Integrating contact network structure into tuberculosis epidemiology in meerkats in South Africa: Implications for control

Empirical studies that integrate information on host contact patterns with infectious disease transmission over time are rare. The aims of this study were to determine the relative importance of intra-group social interactions in the transmission of tuberculosis (TB; Mycobacterium bovis infection) in a population of wild meerkats ( Suricata suricatta) in South Africa, and to use this information to propose an evidence-based intervention strategy to manage this disease. Detailed behavioural observations of all members of eight meerkat groups ( n = 134 individuals) were made over 24 months from January 2006 to December 2007. Social network analysis of three types of interaction (aggression, foraging competitions and grooming) revealed social structure to be very stable over time. Clustering of interactions was positively correlated with group size for both aggression ( r = 0.73) and grooming interactions ( r = 0.71), suggesting that infections may spread locally within clusters of interacting individuals but be limited from infecting all members of large groups by an apparent threshold in connections between different clusters. Repeated biological sampling every three months of all members of one social group ( n = 37 meerkats) was undertaken to quantify individual changes in M. bovis infection status. These empirical data were used to construct a dynamic network model of TB transmission within a meerkat group. The results indicated that grooming (both giving and receiving) was more likely than aggression to be correlated with M. bovis transmission and that groomers were at higher risk of infection than groomees. Intervention strategies for managing TB in meerkats that focus on those individuals engaging in the highest amount of grooming are therefore proposed.

Moving calls: a vocal mechanism underlying quorum decisions in cohesive groups.

Members of social groups need to coordinate their behaviour when choosing between alternative activities. Consensus decisions enable group members to maintain group cohesion and one way to reach consensus is to rely on quorums. A quorum response is where the probability of an activity change sharply increases with the number of individuals supporting the new activity. Here, we investigated how meerkats (Suricata suricatta) use vocalizations in the context of movement decisions. Moving calls emitted by meerkats increased the speed of the group, with a sharp increase in the probability of changing foraging patch when the number of group members joining the chorus increased from two up to three. These calls had no apparent effect on the group's movement direction. When dominant individuals were involved in the chorus, the group's reaction was not stronger than when only subordinates called. Groups only increased speed in response to playbacks of moving calls from one individual when other group members emitted moving calls as well. The voting mechanism linked to a quorum probably allows meerkat groups to change foraging patches cohesively with increased speed. Such vocal coordination may reflect an aggregation rule linking individual assessment of foraging patch quality to group travel route.

Multi-generational persistence of traditions in neighbouring meerkat groups

Reports of socially transmitted traditions based on behavioural differences between geographically separated groups of conspecifics are contentious because they cannot exclude genetic or environmental causes. Here, we report persistent differences between neighbouring groups of meerkats (Suricata suricatta) where extensive gene flow precludes genetic differentiation. Over 11 years, some groups consistently emerged later from their sleeping burrows in the morning than others, despite complete turnovers in group membership and the influx of immigrants. Group territories overlapped and, in many cases, the same sleeping burrows were used by different groups. Differences persisted even after accounting for effects of group size, weather and burrow characteristics, and were unrelated to food availability within territories. These results provide compelling evidence that the emergence times of meerkat groups represent conservative traditions.