Meerkat database

Behav Ecol Sociobiol (2009) 63:1259–1268

Joah R. Madden & Hans-Joerg P. Kunc & Sinead English & Marta B. Manser & Tim H. Clutton-Brock

Adults vary in their generosity in provisioning the young and their sensitivity to the need of the young. Do the young modulate their behaviour so as to specifically target more high-provisioning adults? This is especially likely in situations with mobile, nutritionally dependent young. We studied cooperatively breeding meerkats Suricata suricatta, in which pups beg to parents and other adults in the group. We found that the young begged differently when next to different adults and that they are consistent in how they beg when next to each adult. Pups next to adults that provision at high rates beg at higher rates and spend longer with them, and these adults are generally more sensitive to increases in begging rate. Such behaviour has adaptive benefits to offspring in terms of increased likelihood of being fed. However, offspring do not appear to be actively seeking out high-provisioning adults or increasing their begging behaviour when they encounter one. Pups did not appear to actively discriminate between adults in their association or begging behaviour. We suggest instead that the relationship between an adult’s relative contribution to pup feeding and the behaviour of its accompanying pup is driven by adult behaviour, with responsive adults that feed pups at a relatively higher rate preferentially associating with fast-begging hungry pups.

Keywords: Begging . Meerkats . Provisioning . Sexual conflict . Parent–offspring conflict

Animal Behaviour 78 (2009) 85–89

Joah R. Madden, Hans-Joerg P. Kunc, Sinead English, Tim H. Clutton-Brock

Begging by young provokes adults to provide food for them. However, eventually begging by young and provisioning by adults cease and young become nutritionally independent. Why do young cease begging and so forgo food brought to them by adults? Three explanations have been proposed: (1) adults may not respond to begging anymore and cease feeding begging young; (2) young may voluntarily switch from begging to independent foraging as they gain more rewards from this; (3) young may become unable to produce stimulating begging calls. We tested these three explanations using meerkat, Suricata suricatta, pups. Playback of begging calls at groups where begging had naturally ceased provoked adults to resume provisioning, suggesting that adults had not stopped responding to begging. Experimental provision of food to pups mimicking either natural pup feeding or foraging success produced no differences in subsequent changes in begging or foraging behaviour, suggesting that pups were not assessing the most rewarding means of obtaining food and switching from begging to foraging accordingly. The begging calls of pups (aged 40–60 days) were acoustically different to those produced when they were juveniles (aged 100–120 days), and adults discriminated between rate-controlled playbacks of the two age classes of calls, delivering less food to calls of a juvenile than to the same individual’s calls recorded when a pup. Adult meerkats paid attention to the acoustic structure of begging calls, and ceased provisioning when the call structure changed. We suggest that older pups are unable to produce stimulating begging calls.

Keywords: adult provisioning, begging, independent foraging, meerkat,Suricata suricatta

Behav Ecol Sociobiol (2009) 63: 1097–1107

Aliza le Roux & Michael I. Cherry & Lorenz Gygax & Marta B. Manser

Vigilance behaviour in gregarious species has been studied extensively, especially the relationship between individual vigilance and group size, which is often negative. Relatively little is known about the effect of conspecifics on vigilance in non-obligate social species or the influence of sociality itself on antipredator tactics. We investigated predator avoidance behaviour in the yellow mongoose, Cynictis penicillata, a group-living solitary forager, and compared it with a sympatric group-living, group-foraging herpestid, the meerkat, Suricata suricatta. In yellow mongooses, the presence of conspecifics during foraging — an infrequent occurrence — reduced their foraging time and success and increased individual vigilance, contrary to the classical group-size effect. Comparing the two herpestids, sociality did not appear to affect overt vigilance or survival rates but influenced general patterns of predator avoidance. Whereas meerkats relied on communal vigilance, costly vigilance postures, and auditory warnings against danger, yellow mongooses avoided predator detection by remaining close to safe refuges and increasing “low- cost” vigilance, which did not interfere with foraging. We suggest that foraging group size in herpestids is constrained by species-distinct vigilance patterns, in addition to habitat and prey preference.

Keywords: Group foraging . Meerkats . Solitary foraging . Vigilance . Yellow mongoose

Naturwissenschaften (2009) 96: 575–584

Aliza Le Roux & Michael I. Cherry & Marta B. Manser

We describe the vocal repertoire of a facultatively social carnivore, the yellow mongoose, Cynictis penicillata. Using a combination of close-range observations, recordings and experiments with simulated predators, we were able to obtain clear descriptions of call structure and function for a wide range of calls used by this herpestid. The vocal repertoire of the yellow mongooses comprised ten call types, half of which were used in appeasing or fearful contexts and half in aggressive interactions. Data from this study suggest that the yellow mongoose uses an urgency-based alarm calling system, indicating high and low urgency through two distinct call types. Compared to solitary mongooses, the yellow mongoose has a large proportion of ‘friendly’ vocalisations that enhance group cohesion, but its vocal repertoire is smaller and less context-specific than those of obligate social species. This study of the vocal repertoire of the yellow mongoose is, to our knowledge, the most complete to have been conducted on a facultatively social species in its natural habitat.

Keywords: Mongoose . Sociality . Urgency-based . Vocal repertoire

Animal Behaviour (2009) 78: 791–800

Linda I. Hollen, Andrew N. Radford

Alarm calling is a widespread antipredator behaviour. Although the function and evolution of alarm call behaviour have long been studied in detail, only in the last decade has there been an upsurge in research into its development. Here, we review the literature on the development of alarm call production (the delivery of calls with a specific set of acoustic features), alarm call usage (the use of calls in particular contexts) and alarm call responses (the responses to calls produced by others). We detail the mechanistic processes that may underlie the development of each aspect, consider the selection pressures most likely to explain the relative importance of these processes, and discuss the substantial variation in develop- mental rates found both between and within species. Throughout, we interpret existing findings about age-related differences in alarm call behaviour from two major communicatory viewpoints: the idea that signals carry information from sender to receiver, with young taking time to acquire adult-like skills; and the possibility that signals are used to manage the behaviour of receivers, with young behaving adaptively for their age. We conclude that a broader use of various techniques (e.g. cross-fostering and temporary removals), the formation of stronger collaborative links with other disciplines (e.g. physiology and neurobiology) and the initiation of new research avenues (e.g. kleptoparasitism) will ensure that studies on the development of alarm call behaviour continue to enhance our understanding of such topics as the evolution of communication and language, kin selection and cognitive processing.

Keywords:

alarm calling, assessment–management, call production, call responses, call usage, development, information transfer, learning, maturation, vocal communication

Behavioral Ecology (2009), 20: 930-935

S.J. Hodge, A. Thornton, T.P. Flower and T.H. Clutton-Brock

Both the rate and severity of sibling aggression are predicted to be higher when food availability is low. Although there is now good evidence that food availability influences sibling aggression in facultatively siblicidal species, where aggression commonly results in the death of a competitor, little is known about the proximate causes of aggression in nonsiblicidal species, where aggression rarely results in serious injury. Here, we investigated patterns of aggression between juvenile meerkats (Suricata suricatta), a species where littermate aggression is common, but never lethal. We show that the frequency of aggression between littermates increased when rainfall and helper number, both predictors of the amount of food available to pups, were low. Short-term feeding experiments demonstrated that reducing pup hunger by provisioning them before a foraging session significantly reduced their frequency of aggression in comparison to unfed controls. There was no evidence that offspring sex or weight influenced either the rate at which pups were aggressive, or which littermates they were aggressive to. These results suggest that food availability is an important factor affecting the severity of aggressive competition between offspring, even in the absence of lethal aggressive attacks.

Key words: aggression, agonism, competition, dominance, food amount hypothesis, siblicide, sibling rivalry, Suricata suricatta.

J Vet Diagn Invest (2009), 21: 31–39

Julian A. Drewe, Gillian S. Dean, Anita L. Michel, Gareth P. Pearce

Accurate diagnosis of Mycobacterium bovis infection (bovine tuberculosis [bTB]) in live animals is notoriously problematic. The aim of the present study was to evaluate the diagnostic potential of 2 new serologic tests (multiantigen print immunoassay [MAPIA] and lateral flow immunoassay rapid test [RT]) in comparison with mycobacterial culture of tracheal washes for determining M. bovis infection status in a free- ranging population of wild meerkats (Suricata suricatta). During a longitudinal study lasting 2.5 years, 240 individually identifiable meerkats were each sampled up to 8 times under anesthesia every 3 months. Diagnostic accuracy was determined through Bayesian and maximum likelihood estimations of sensitivity, specificity, and likelihood ratios for each diagnostic test when used independently and in parallel to classify the disease status of individual meerkats in the absence of a gold standard. Culture of tracheal washes was highly specific (0.99; 95% confidence interval [CI] 5 0.77, 1.00) but of low sensitivity (0.36; 95% CI 5 0.24, 0.50) for diagnosing M. bovis–infected individuals. The longitudinal nature of the study with repeated sampling of the same individual animals served simultaneously to improve chances of detecting infection and increase confidence in a negative result in individual animals repeatedly testing negative. Although MAPIA and RT were individually of limited diagnostic use, interpreting the results of these 2 tests in parallel produced estimates of sensitivity (0.83; 95% CI 5 0.67, 0.93) and specificity (0.73; 95% CI 5 0.62, 0.82) high enough to usefully inform decision making when determining exposure to bTB in wild meerkats and potentially other species in which bTB poses a diagnostic challenge.

Keywords: Diagnosis; meerkats; Mycobacterium bovis; serologic test; tuberculosis; wildlife.

J. Comp. Path. (2009), Vol. 140, 12-24

J. A. Drewe, A. K. Foote, R. L. Sutcliffe and G. P. Pearce

Pathological lesions associated with Mycobacterium bovis infection (bovine tuberculosis; bTB) in free-living meerkats (Suricata suricatta) in the Kalahari Desert of South Africa are described. The pathology of bTB in meerkats was determined through detailed post-mortem examinations of 57 animals (52 meerkats showing clinical signs of bTB, and five not showing signs of disease). Lymph nodes and tissue lesions thought to be associated with bTB were cultured for mycobacteria. All 52 bTB-infected meerkats showed gross or microscopical granulomatous lesions, but M. bovis was cultured from only 42% (22/52) of these animals. The majority (96%, 50/52) of diseased meerkats had lesions in multiple sites, the pattern of which suggested haematogenous spread of M. bovis infection in this species. The histological characteristics of the tuberculous lesions, together with the gross pathology and the wide range of body systems affected, indicate that infection in meerkats is acquired principally via the respiratory and oral routes, whereas excretion is most likely via the respiratory tract and suppurating skin wounds. Urine and faeces appear to be unlikely sources of infection. The findings of this study provide information on the transmission, pathogenesis and epidemiology of bTB in meerkats that is likely to be relevant to the understanding of M. bovis infection in other social mammal species such as the European badger (Meles meles).

Keywords: meerkat; Mycobacterium bovis; pathology; Suricata suricatta; tuberculosis

Behav Ecol Sociobiol (2009) 63:1295–1306

J. A. Drewe & J. R. Madden & G. P. Pearce

Groups of individuals frequently interact with each other, but typically analysis of such interactions is restricted to isolated dyads. Social network analysis (SNA) provides a method of analysing polyadic interactions and is used to analyse interactions between individuals. We use a population of 12 groups (ca. 250 animals) of wild meerkats (Suricata suricatta) to test whether SNA can also be used to describe and elucidate patterns of inter-group interactions. Using data collected over 24 months, we constructed two sets of networks, based on direct encounters between groups and instances of roving males visiting other groups. We analysed replicated networks of each type of interaction to investigate similarities between networks of different social interactions as well as testing their stability over time. The two network types were similar to each other when derived from long-term data, but showed significant differences in structure over shorter timescales where they varied according to seasonal and ecological conditions. Networks for both types of inter-group interaction constructed from data collected over 3 months reliably described long-term (12- and 24-month) patterns of interactions between groups, indicating a stable social structure despite variation in group sizes and sex ratios over time. The centrality of each meerkat group in roving interactions networks was unaffected by the sex ratio of its members, indicating that male meerkats preferentially visit geographically close groups rather than those containing most females. Indeed, the strongest predictors of network structure were spatial factors, suggesting that, in contrast to analyses of intra-group interactions, analyses of inter-group interactions using SNA must take spatial factors into account.

Keywords:  Social networks, Meerkats, Inter-group encounters, Roving males, Spatial factors

The American Naturalist (2009), 173, 3: 400-410

Roman D. Furrer and Marta B. Manser

A major evolutionary force driving functionally referential alarm calls is the need for different strategies to escape various predator types in complex structured habitats. In contrast, a single escape strategy appears to be sufficient in less-structured open habitats, and under such conditions urgency-dependent alarm calls may be favored. Nevertheless, some species, such as meerkats (Suricata suricatta), have evolved functionally referential alarm calls despite living in open areas, using only bolt-holes for retreat. To understand the evolution of different alarm call systems, we investigated the calls of sympatric Cape ground squirrels (Xerus inauris) and compared their antipredator and foraging behavior with that of meerkats. Cape ground squirrels emitted urgency-dependent alarm calls and responded to playbacks depending on urgency, not predator type. Vigilance behavior and habitat use differed between the two species. Meerkats roam widely to find prey and for efficient foraging depend on coordinated predator vigilance and escape behavior. As herbivores with smaller territories, Cape ground squirrels depend less on coordinated antipredator behavior, and urgency-dependent alarm calls encode all essential information. We conclude that habitat complexity does not explain the evolution of functionally referential alarm calls in all species, and other constraints, such as the need to coordinate group movements to maintain foraging efficiency, could be more relevant.

Keywords: vocal communication, alarm calls, functionally referential alarm calls, urgency-based alarm calls.