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Sexual dimorphism, activity budget and synchrony in groups of sheep

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The activity budget hypothesis has been proposed to explain the social segregation commonly observed in ungulate populations. This hypothesis suggests that differences in body size – i.e. between dimorphic males and females – may account for differences in activity budget. In particular, if females spend more time grazing and less time resting than males, activity synchrony would be reduced. Increased costs of maintaining synchrony despite differences in activity budget would facilitate group fragmentation and instability of mixed-sex groups. In this paper two prerequisites of the activity budget hypothesis were tested: (1) that males should spend less time feeding and more time resting than females in single-sex groups and (2) that lower activity synchrony should be observed in mixed-sex compared to single-sex groups. The activity budget and synchrony in mixed and single-sex groups of merino sheep (Ovis aries) of different sizes (2, 4, 6, 8 individuals) were measured in three contiguous 491-m2 arenas located in a natural pasture. Three same-size groups, one of each category, were observed simultaneously. We found no sexual differences in the time spent inactive and active (i.e. grazing, standing, moving, interacting). Males spent significantly more time grazing and less time standing than females. These differences disappeared when yearling males were omitted from the group. Males and females had similar bite and step rates. Sheep of both sexes spent less time resting and more time grazing and moving and had lower bite rates when in mixed-sex groups than when in single-sex groups. The synchrony among visually isolated groups was near zero, indicating that they changed activities independently. On the contrary, within-group synchrony was high; however it was higher in single-sex groups, in particular for males, than in mixed-sex groups. Our results suggest that differences in activity budget and synchrony alone are insufficient to explain social segregation.

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  1. Barthram GT (1986) Experimental techniques, the HFRO sward stick. In: Biennial Report 1984–1985, Hill Farming Research Organisation, Penicuik

  2. Blanc F, Thériez M, Brelurut A (1999) Effects of mixed-species stocking and space allowance on the behaviour and growth of red deer hinds and ewes at pasture. Appl Anim Behav Sci 63:41–43

  3. Bleich VC, Bowyer RT, Wehausen JD (1997) Sexual segregation in mountain sheep: resources or predation? Wildl Monogr 134:1–10

  4. Bon R (1991) Social and spatial segregation of males and females in polygamous ungulates: proximate factors. In: Spitz F, Janeau G, Gonzalez G, Aulagnier S (eds) Ongulés/Ungulates. SFEPM-IRGM, Paris-Toulouse, pp 195–198

  5. Bon R, Campan R (1996) Unexplained sexual segregation in polygamous ungulates: a defense of an ontogenetic approach. Behav Process 38:131–154

  6. Bon R, Rideau C, Villaret J-C, Joachim J (2001) Segregation is not only a matter of sex in Alpine ibex, Capra ibex ibex. Anim Behav 62:495–504

  7. Bon R, Deneubourg J-L, Gerard J-F, Michelena P (2005) Sexual segregation in ungulates: from individual mechanisms to collective patterns. In: Ruckstuhl K, Neuhaus P (eds) Sexual segregation in vertebrates. Cambridge University Press, Cambridge

  8. Bonenfant C, Loe LE, Mysterud A, Langvatn R, Stenseth NC, Gaillard JM, Klein F (2004) Multiple causes of sexual segregation in European red deer: enlightenments from varying breeding phenology at high and low latitude. Proc R Soc London Ser B Biol Sci 271:883–892

  9. Bosc P, Fabre P, Hubert D, Molénat G (1999) Influence de l’époque de pâturage des regrains de prés de Crau sur quelques paramètres de production de la prairie. Fourrages 157:33–45

  10. Bowyer RT (2004) Sexual segregation in ruminants: definitions, hypotheses, and implications for conservation and management. J Mammal 85:1039–1052

  11. Bowyer RT, Kie JG (2004) Effects of foraging activity on sexual segregation in mule deer. J Mammal 85:498–504

  12. Champion RA, Orr RJ, Penning PD, Rutter SM (2004) The effect of the spatial scale of heterogeneity of two herbage species on the grazing behaviour of lactating sheep. Appl Anim Behav Sci 88:61–76

  13. Clayton DA (1978) Socially facilitated behavior. Q Rev Biol 53:373–392

  14. Conradt L (1998a) Measuring the degree of sexual segregation in group-living animals. J Anim Ecol 67:217–226

  15. Conradt L (1998b) Could asynchrony in activity between the sexes cause intersexual social segregation in ruminants? Proc R Soc London Ser B Biol Sci 265:1359–1363

  16. Conradt L (1999) Social segregation is not a consequence of habitat segregation in red deer and feral soay sheep. Anim Behav 57:1151–1157

  17. Conradt L, Roper TJ (2000) Activity synchrony and social cohesion: a fission–fusion model. Proc R Soc London Ser B Biol Sci 267:2213–2218

  18. Conradt L, Roper TJ (2003) Group decision-making in animals. Nature 421:155–158

  19. Corti P, Shackleton DM (2002) Relationship between predation risk factors and sexual segregation in Dall’s sheep (Ovis dalli dalli). Can J Zool 80:2108–2117

  20. Côté SD, Schaefer JA, Messier F (1997) Time budgets and synchrony in activity in muskoxen: the influence of sex, age and season. Can J Zool 75:1628–1635

  21. Cransac N, Gerard J-F, Maublanc ML, Pépin D (1998) An example of segregation between age and sex classes only weakly related to habitat use in mouflon sheep (Ovis gmelini). J Zool 244:371–378

  22. Deneubourg J-L, Goss S (1989) Collective patterns and decision making. Ethol Ecol Evol 1:295–311

  23. Dubois M, Quenette PY, Bideau E, Magnac MP (1993) Seasonal range use by European mouflon rams in medium altitude mountains. Acta Theriol 38:185–198

  24. Dumont B, Boissy A (2000) Gazing behaviour of sheep in situation of conflict between feeding and social motivations. Behav Process 49:131–138

  25. Ginnett TF, Demment MW (1997) Sex differences in giraffe foraging behavior at two spatial scales. Oecologia 110:291–300

  26. Kie JG, Bowyer RT (1999) Sexual segregation in white-tailed deer: density-dependent changes in use of space, habitat selection, and dietary niche. J Mammal 80:1004–1020

  27. Kohlmann SG, Müller DM, Alkon PU (1996) Antipredator constraints on lactating nubian ibexes. J Mammal 77:1122–1131

  28. Maier JAK, White RG (1998) Timing and synchrony of activity in caribou. Can J Zool 76:1999–2009

  29. Main MB, Weckerly FW, Bleich VC (1996) Sexual segregation in ungulates: new directions for research. J Mammal 77:449–461

  30. Michelena P, Bouquet PM, Dissac A, Fourcassie V, Lauga J, Gerard JF, Bon R (2004) An experimental test of hypotheses explaining social segregation in dimorphic ungulates. Anim Behav 68:1371–1380

  31. Mooring MS, Fitzpatrick TA, Benjamin JE, Fraser IC, Nishihira TT, Reisig DD, Rominger EM (2003) Sexual segregation in desert bighorn sheep (Ovis canadensis mexicana). Behaviour 140:183–207

  32. Mysterud A (1998) The relative roles of body size and feeding type on activity time of temperate ruminants. Oecologia 113:442–446

  33. Mysterud A (2000) The relationship between ecological segregation and sexual body size dimorphism in large herbivores. Oecologia 124:40–54

  34. Neuhaus P, Ruckstuhl KE (2002) Foraging behaviour in Alpine ibex (Capra ibex): consequences of reproductive status, body size, age and sex. Ethol Ecol Evol 14:373–381

  35. Orr RJ, Penning PD, Harvey A, Champion RA (1997) Diurnal patterns of intake rate by sheep grazing monocultures of ryegrass or white clover. Appl Anim Behav Sci 52:65–77

  36. Penning PD, Parsons AJ, Newman JA, Orr RJ, Harvey A (1993) The effect of group size on grazing time in sheep. Appl Anim Behav Sci 37:101–109

  37. Pérez-Barbería FJ, Gordon IJ (1998) The influence of sexual dimorphism in body size and mouth morphology on diet selection and sexual segregation in cervids. Acta Vet Hung 46:357–367

  38. Pérez-Barbería FJ, Gordon IJ (1999a) Body size dimorphism and sexual segregation in polygynous ungulates: an experimental test with Soay sheep. Oecologia 120:258–267

  39. Pérez-Barbería FJ, Gordon IJ (1999b) The relative roles of phylogeny, body size and feeding style on the activity time of temperate ruminants: a reanalysis. Oecologia 120:193–197

  40. Ramirez Avila GM, Guisset JL, Deneubourg JL (2003) Synchronization in light-controlled oscillators. Physica D 182:254–273

  41. Rook AJ, Penning PD (1991) Synchronisation of eating, ruminating and idling activity by grazing sheep. Appl Anim Behav Sci 32:157–166

  42. Ruckstuhl KE (1998) Foraging behaviour and sexual segregation in bighorn sheep. Anim Behav 56:99–106

  43. Ruckstuhl KE, Neuhaus P (2000) Sexual segregation in ungulates: a new approach. Behaviour 137:361–377

  44. Ruckstuhl KE, Neuhaus P (2001) Behavioral synchrony in ibex groups: effects of age, sex and habitat. Behaviour 138:1033–1046

  45. Ruckstuhl KE, Neuhaus P (2002) Sexual segregation in ungulates: a comparative test of three hypotheses. Biol Rev Cambridge Philos Soc 77:77–96

  46. Ruckstuhl KE, Neuhaus P (2005) Sexual segregation in vertebrates: ecology of the two sexes. Cambridge University Press, Cambridge

  47. Ruckstuhl KE, Festa-Bianchet M, Jorgenson JT (2003) Bites rates in Rocky Mountain bighorn sheep (Ovis canadensis): effects of season, age, sex and reproductive status. Behav Ecol Sociobiol 54:167–173

  48. Siegel S, Castellan NJ (1988) Nonparametric statistics for the behavioral sciences, 2nd edn. McGraw-Hill, New-York

  49. Weckerly FW (1993) Intersexual resource partitioning in black-tailed deer: a test of the body size hypothesis. J Wildl Manag 57:475–494

  50. Weckerly FW, Ricca MA, Meyer KP (2001) Sexual segregation in Roosevelt elk: Cropping rates and aggression in mixed-sex groups. J Mammal 82:825–835

  51. Yearsley JM, Javier Perez-Barberia F (2005) Does the activity budget hypothesis explain sexual segregation in ungulates? Anim Behav 69:257–267

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We thank Hervé Monod, Michel Goulard and Alain Baccini for statistical assistance and Jean-Pierre Theau for help with the grass measurements. We acknowledge the participation of Cathy Boléat and Virginia Colom in data collection and that of the staff of the Domaine du Merle for technical assistance. Vincent Fourcassié and the two anonymous referees provided valuable comments on the manuscript. Special thanks are addressed to Richard H. Porter for English revision. Pablo Michelena and Jacques Gautrais were supported by the LEURRE project sponsored by the Future and Emerging Technologies program of the European Community (IST-2001-35506). Animal care and experimental manipulations were in accordance with the rules of the French committee of animal experimentation ethics.

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Correspondence to Pablo Michelena.

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Communicated by Hannu Ylonen

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Michelena, P., Noël, S., Gautrais, J. et al. Sexual dimorphism, activity budget and synchrony in groups of sheep. Oecologia 148, 170–180 (2006). https://doi.org/10.1007/s00442-005-0347-2

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  • Allelomimetism
  • Body mass
  • Ruminant
  • Social segregation
  • Time budget