Specialization in the Standing Guard Duty of Captive Meerkats ( Suricata suricatta ) By Jason Gue 1. Fort Lewis College

1. Specialization in the Standing Guard Duty of Captive Meerkats • (Suricata suricatta) • By • Jason Gue • 1. Fort Lewis College, Department of Biology, Durango, CO. • 2. Cheyenne Mountain Zoo, Colorado Springs, CO. CHEYENNE MOUNTAIN ZOO INTRODUCTION • KEY FINDINGS • In captivity male meerkats conduct more standing guard than females • Subordinates conduct more standing guard than the Dominant pair in captivity • In captivity different litters conduct more standing guard than others • In captivity there is an interaction between the time of day and litter when conducting standing guard • In captivity this is no connection between time of day and gender A meerkat (Suricata suricatta) is a diurnal, desert-adapted social mongoose that lives in groups called mobs that consist of 2 to 30 individuals in Southern Africa (Macdonald, 1986; Clutton-Brock et al., 1999). Meerkats contribute within their mob by conducting several different cooperative behaviors. The most common behaviors are babysitting the pups (1-3 months old), pup/juvenal feeding (2-6 months old), social digging of burrows, group foraging and anti-predator defenses (Macdonald, 1986; Bednekoff, 1997; Clutton-Brock et al., 1998, 2002). The standing guard behavior is one of the anti-predator defenses, where an individual leaves foraging to obtain a position that is relatively unprotected to observe for potential predators (Bednekoff, 1997) Clutton-Brock et al. (2003) studied social behavior by meerkats in the wild and showed no evidence of specialized behavior in cooperative activities based on sex and/or age. However, other researchers have found that nutritional status from foraging does influence which individual is on standing guard duty and for how long (Cant and Field, 2001; Clutton-Brock et al., 1999, 2003) I hypothesized that when meerkats are in controlled populations (zoological park) where foraging does not dominate the majority of their time and nutritional status is constant, they will take on specialized roles to better contribute to the vitality of the mob. If meerkats do in fact take on a specialized role in social behaviors, then it should be evident in the standing guard duty because they are all in the same nutritional state. Figure 4. Female meerkat on standing guard at Cheyenne Mountain Zoo, Colorado Springs, CO. 2006. Photo by Jason Gue a) b) Figure 2. Comparison of standing guard conducted by dominant pair and subordinates (18 individuals; t = -3.6, p = 0.001, Independent t-test, standard error is shown) Figure 5. Average time daily (min) that males and females conducted standing guard within their litter designation. The dominant male and females were not factored in. Litters 1, 2 and 3 had no males because they have been removed because of behavior. Litter 4 was a single male birth with no females. Litter 1 conducted standing guard significantly more than litter 6 (p = 0.0). Litter 2 stood guard significantly more over litter 3 (p = 0.012), litter 6 (p = 0.0) and was marginally less significant than litter 5 (p = .058). Litter 3 conducted standing guard significantly less than litter 2 (p = 0.012) and litter 4 (p = 0.003). Litter 4 conducted standing guard significantly more that litter 3 (p = 0.003) and litter 6 (p = 0.0) while significantly less than litter 5 (p = 0.024). Litter 5 conducted standing guard significantly more then litter 4 (p = 0.024), litter 6 (p = 0.0), and had marginal significance over litter 2 (p = 0.058). Litter 6 was significantly less than litter 1, 2, 4, 5 (p = 0.0). (n = 702 occurrences of standing guard; F = 24.0, p = 0.0 using a one-way ANOVA with Tukey’s post hoc test, standard error is shown) Figure 8. Male meerkat on standing guard at Cheyenne Mountain Zoo, Colorado Springs, CO. 2006, Photoby Jason Gue c) REFERENCES Bednekoff, P.A. 1997. Mutualism among safe, selfish sentinels: a dynamic game. American Naturalist. Vol. 150. 3:373-392 Bekoff, M. 1979. Behavioral acts: description, classification, ethogram analysis, and measurement.  Pgs. 67-80, in The analysis of social interactions: methods, issues, and illustrations (edited by R. C. Cairns). Lawrence Erlbaum Associates, Hillsdale, New Jersey. Cant, M.A. and J. Field. 2001. Helping effort and future fitness in cooperative animal societies. Proceedings of the Royal Society of London, Series B, 268:1959-1964. Clutton-Brock, T.H., D. Gaynor, R. Kansky, A.D.C. MacColl, G. McIlrath, P. Chadwick, P.N.M. Brotherton, J.M. O’Riain, M. Manser and J.D. Skinner. 1998. Cost of cooperative behaviour in suricates (Suricata suricatta). Proceedings of the Royal Society of London, Series B, 265:185-190. Clutton-Brock, T.H., M.J. O’Riain, P.N.M. Brotherton, D. Gaynor, R. Kansky, A.S. Griffin and M. Manser. 1999. Selfish sentinels in cooperative mammals. Science. 284:1640-1644. Clutton-Brock, T.H., A.F. Russell, L.L. Sharp, A.J. Young, Z. Balmforth and G.M. McIlrath. 2002. Evolution and development of sex differences in cooperative behavior in meerkats. Science. 297:253-256. Clutton-Brock, T.H., A.F. Russell and L.L. Sharpe. 2003. Meerkat helpers do not specialize in particular activities. Animal Behaviour. 66:531-540. Macdonald, D.W. 1986. A meerkat volunteers for guard duty so its comrades can live in peace. Smithsonian. 17:55- 64. Russell, A.F., T.H. Clutton-Brock, P.N.M. Brotherton, L.L. Sharpe, G.M. McIlrath, F.D. Dalerum, E.Z. Cameron and J.A. Bernard. 2002. Factors affecting pup growth and survival in co-operatively breeding meerkats Suricata suricatta. Journal of Animal Ecology. 71:700-709 Sharpe, L.L. and M.I. Cherry. 2003. Social play does not reduce aggression in wild meerkats. Animal Behaviour. 66:989-997 Figure 1. Male meerkat at Cheyenne Mountain Zoo, Colorado Springs, CO. Photoby Jenyva Turner STUDY OBJECTIVES (1) Do captive male or female meerkats conduct standing guard duty at a higher rate? (2) In captivity is the dominant male or female conducting standing guard at a higher rate than the subordinates? (3) In captivity does different litter groups stand guard more than others? (4) Does time of day impact which meerkat is on standing guard in captivity? Figure 7. Comparison of gender by the average time of day that standing guard was observed. All 20 meerkat (15 females, 5 males) had equal opportunity of conducting standing guard during all three observation periods. a) Shows the 0700-0900h watch period; b) is for the 1100-1300h watch period, c) is for the 1600-1800h watch period. The interaction between time of day and gender was insignificant (F = 1.16, p= 0.32, 2-way 3x2 mixed ANOVA, standard error is shown). Figure 3. The average time per day individual meerkats spent on standing guard based on gender. All males (5) and females (15) were accounted for regardless of dominance. (n = 702 occurrences of standing guard during study; F = 8.61, p = 0.003 using a one-way ANOVA with Tukey post hoc test, standard error is show) ACKNOWLEDGMENTS I would like to thank the Fort Lewis College, Department of Biology, especially Dr. Julie Korb and Dr. Joseph Ortega for assisting in research design, suggestions, and comments on my manuscript. This project would not have been possible if it were not for Cheyenne Mountain Zoo, especially, Jenyva Turner, Andie Armbrust, RoxAnna Breitigan, Randy Barker, Dr. Michelle Bowman and Tracy Leeds for allowing me to conduct the study, assisting in marking the meerkats, and letting me work out of the African Rift Valley between observation periods. I would also like to thank Dr. Sue Kraus, Dr. Beverly Chew and Katie Moorstein for donating their time, insight and materials for conducting the statistical analysis. Finally, I would like to thank the meerkats that make their home at Cheyenne Mountain Zoo for being good sports with their “unique hair cuts” and minimal biting. EXPERIMENTAL DESIGN AND METHODS The meerkat mob was grouped by litter to help determine whether their social behaviors are generalized or specialized within the mob. There was a total of 20 meerkats, that were grouped by dominant pair and litters 1 through 6. Each meerkat was given a unique hair cut to insure correct identification during the study period. Observations were conducted at 0700h-0900h, 1100h-1300h, and 1600h-1800h for 39 consecutive days. I have selected these times based upon peak times that meerkats are outside their burrows in a natural setting and zoo operation hours to minimize zoo keeper and general public interference with the meerkats behavior (Clutton-Bock et al., 1999; Russell et al., 2002; Sharp and Cherry, 2002). The method of observation I used for this study was sampling of all occurrences (Bekoff, 1979). Figure 6. Average time on standing guard by time of day and litter with dominant pair included. The interaction between the different times of day and the average amount of time each litter including the dominant pair was significant (F = 5.8, p = 0.004, 2-way 3x7 mixed ANOVA, standard error is shown)