Abstract
Elephants (Loxodonta africana) exhibit pronounced sexual dimorphism, and in this study we test the prediction that the differences in body size and sociality are significant enough to drive divergent foraging strategies and ultimately sexual segregation. Body size influences the foraging behaviour of herbivores through the differential scaling coefficients of metabolism and gut size, with larger bodied individuals being able to tolerate greater quantities of low-quality, fibrous vegetation, whilst having lower mass-specific energy requirements. We test two distinct theories: the scramble competition hypothesis (SCH) and the forage selection hypothesis (FSH). Comprehensive behavioural data were collected from the Pongola Game Reserve and the Phinda Private Game Reserve in South Africa over a 2.5-year period. The data were analysed using sex as the independent variable. Adult females targeted a wider range of species, adopted a more selective foraging approach and exhibited greater bite rates as predicted by the body size hypothesis and the increased demands of reproductive investment (lactation and pregnancy). Males had longer feeding bouts, displayed significantly more destructive behaviour (31% of observations, 11% for females) and ingested greater quantities of forage during each feeding bout. The independent ranging behaviour of adult males enables them to have longer foraging bouts as they experience fewer social constraints than females. The SCH was rejected as a cause of sexual segregation due to the relative abundance of low quality forage, and the fact that feeding heights were similar for both males and females. However, we conclude that the differences in the foraging strategies of the sexes are sufficient to cause spatial segregation as postulated by the FSH. Sexual dimorphism and the associated behavioural differences have important implications for the management and conservation of elephant and other dimorphic species, with the sexes effectively acting as distinct “ecological species”.
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References
Acocks JPH (1988) Veld types of South Africa, 3rd edn. Botanical Research Institute, Pretoria
Anderson M (1994) Sexual selection. Princeton University Press, Princeton, NJ
Barnes RFW (1979) Elephant ecology in Ruaha National Park, Tanzania. PhD Thesis, Cambridge University, Cambridge, UK
Beier P (1987) Sex differences in quality of white-tailed deer diets. J Mammal 68:323–329
Bell RH (1971) A grazing ecosystem in the Serengeti. Sci Am 225:86–93
Blanchard P (2005) On lactation and rumination in bighorn ewes (Ovis Canadensis). J Zool Lond 265:107–112
Bon R, Rideau C, Villaret J, Joachim J (2001) Segregation is not only a matter of sex in Alpine ibex Capra ibex ibex. Anim Behav 62:495–504
Bowyer RT (2004) Sexual segregation in ruminants: definitions, hypotheses and implications for conservation and management. J Mammal 85:1039–1052
Brown JS (2000) Foraging ecology of animals in response to heterogeneous environments. In: Hutchings J, John EA, Stewart A (eds) The ecological consequences of environmental heterogeneity. Blackwell, Oxford, UK, Chap 10, pp 181–214
Charif RA, Ramey RR, Langbauer WR, Payne KB, Martin RB, Brown LM (2005) Spatial relationships and matrilineal kinship in African savanna elephant (Loxodonta africana) clans. Behav Ecol Sociobiol 57:327–338
Clauss M, Frey R, Kiefer B, Lechner-Doll M, Loehlein W, Polster C, Rossner GE, Streich WJ (2003) The maximum attainable body size of herbivorous mammals: morphophysiological constraints on foregut and adaptations of hindgut fermenters. Oecologia 136:14–27
Clutton-Brock TH, Guiness FE (1987) Sexual segregation and density related changes in habitat use in male and female deer (Cervus elephus). J Zool Lond 211:275–289
Clutton-Brock TH, Harvey PH (1978) Mammals, resources and reproductive strategies. Nature 273:191–195
Clutton-Brock TH, Albon SD, Guinness FE (1989) Fitness costs of gestation and lactation in wild mammals. Nature 337:260–262
Conradt L (1998) Could asynchrony in activity between the sexes cause intersexual social segregation in ruminants? Proc Biol Sci 265:1359–1363
Conradt L (1999) Social segregation is not a consequence of habitat segregation in red deer and feral soay sheep. Anim Behav 57:1151–1157
Conradt L, Roper TJ (2003) Group decision-making in animals. Nature 421:155–158
Darwin C (1871) The descent of man, and selection in relation to sex. John Murray, London
Demment MW (1983) Feeding ecology and the evolution of body size of baboons. Afr J Ecol 21:219–233
Demment MW, Van Soest PJ (1985) A nutritional explanation for body size patterns of ruminant and non-ruminant herbivores. Am Nat 125:641–672
East R (1984) Rainfall, soil nutrient status and biomass of large African savanna mammals. Afr J Ecol 22:245–270
Fritz H, De Garine Whichatitsky M (1996) Foraging in a social antelope: effects of group size on foraging choices and resource perception in impala. J Anim Ecol 65:736–742
Garaï ME, Slotow R, Carr RD, Reilly B (2004) Elephant reintroductions to small fenced reserves in South Africa. Pachyderm 37:28–36
Ginnet TF, Demment MW (1999) Sexual segregation by Masai giraffes at two spatial scales. Afr J Ecol 37:93–106
Guy PR (1976) The feeding behaviour of elephants (Loxodonta africana) in the Sengwa area of Rhodesia. S Afr J Wildl Res 6:55–63
Illius AW, Gordon IJ (1987) The allometry of food intake in grazing ruminants. J Anim Ecol 56:989–999
Jarman PJ (1974) The social organisation of antelope in relation to their ecology. Behaviour 48:215–266
Jetz W, Carbone C, Fulford J, Brown JH (2004) The scaling of animal space use. Science 306:266–268
Kleiber M (1961) The fire of life: an introduction to animal energetics. Wiley, New York
Krebs JR, Davies NB (1993) An introduction to behavioural ecology, 3rd edn. Blackwell, Oxford, UK
Laws RM (1970) Elephants as agents of habitats and landscape change in East Africa. Oikos 21:1–15
Laws RM, Parker ISC, Johnstone RCB (1975) Elephants and their habitats. The ecology of elephants in Northern Bunyoro, Uganda. Clarendon Press, Oxford, UK
Le Blanc M, Festa-Bianchet M, Jorgenson JT (2001) Sexual size dimorphism in bighorn sheep (Ovis canadensis): effects of population density. Can J Zool 79:1661–1670
Lee PC, Moss CJ (1995) Satural growth in known-age African elephants (Loxodonta africana). J Zool Lond 236:29–41
Loison A, Gaillard J, Pelabon C, Yoccoz NG (1999) What factors shape sexual size dimorphism in ungulates? Evol Ecol Res 1:611–633
Loudon ASI (1985) Lactation and neonatal survival of mammals. Symp Zool Soc Lond 54:183–207
Low AB, Rebelo AG (eds) (1996) Vegetation of South Africa, Lesotho and Swaziland. Department of Environmental Affairs and Tourism, Pretoria
Main MB, Weckerley FW, Bleich VC (1996) Sexual segregation in ungulates: new directions for research. J Mammal 77:449–461
McComb K, Moss C, Durant SM, Baker L, Sayialel S (2001) Social knowledge in African elephants. Science 292:491–494
McElligott AG, Gammell MP, Harty HC, Paini DR, Murphy DT, Walsh JT, Hayden TJ (2001) Sexual size dimorphism in fallow deer (Dama dama): do larger, heavier males gain greater mating success? Behav Ecol Sociobiol 49:266–272
McNaughton SJ, Georgiadis NJ (1986) Ecology of African grazing and browsing mammals. Annu Rev Ecol Syst 17:39–65
Michelena P, Noël S, Gautrais J, Gerard J, Deneubourg J, Bon R (2006) Sexual dimorphism, activity budget and synchrony in groups of sheep. Oecologia 148:170–180
Midgley JJ, Balfour D, Kerley G (2005) Why do elephants damage savanna trees? S Afr J Sci 101:213–215
Moss CJ, Poole JH (1983) Relationships and social structure of African elephants. In: Hinde RA (ed) Primate social relations. Blackwell, Oxford, UK, pp 315–325
Murray M, Brown D (1993) Niche separation of grazing ungulates in the Serengeti: an experimental test. J Anim Ecol 62:380–389
Mysterud A (1998) The relative roles of body size and feeding type on activity time of temperate ruminants. Oecologia 113:442–446
Owen-Smith N (1992) Megaherbivores: the influence of very large body size on ecology. Cambridge University Press, Cambridge, UK
Owen-Smith N (1998) How high ambient temperature affects the daily activity and foraging time of a subtropical ungulate, the greater kudu (Tragelaphus strepsiceros). J Zool Lond 246:183–192
Pelletier F, Festa-Bianchet M (2004) Effects of body mass, age, dominance and parasite load on foraging time of big horn rams, Ovis canadensis. Behav Ecol Sociobiol 56:546–551
Peters RH (1983) The ecological implications of body size. Cambridge University Press, Cambridge, UK
Poole JH (1994) Sex differences in the behaviour of African elephants. In: Short RV, Balaban E (eds) The difference between the sexes. Cambridge University Press, Cambridge, UK, pp 331–346
Prins HHT, Loth PE (1988) Rainfall patterns as a background to plant phenology in northern Tanzania. J Biogeogr 15:451–46
Rands SA, Colishaw G, Pettifor RA, Rowcliffe JM, Johnson RA (2003) Spontaneous emergence of leaders and followers in foraging pairs. Nature 423:432–434
Ruckstuhl KE (1998) Foraging behaviour and sexual segregation in bighorn sheep. Anim Behav 55:99–106
Ruckstuhl KE, Neuhaus P (2000) Sexual segregation in ungulates: a new approach. Behaviour 137:361–377
Ruckstuhl KE, Festa-Bianchet M, Jorgenson JT (2003) Bite rates in rocky mountain bighorn sheep (Ovis canadensis): effects of season, age sex and reproductive status. Behav Ecol Sociobiol 54:167–173
Ruggiero RG (1992) Seasonal forage utilisation by elephants in central Africa. Afr J Ecol 30:137–148
Seagle SW, McNaughton SJ (1992) Spatial variation in forage nutrient concentrations and the distribution of Serengeti grazing ungulates. Landscape Ecol 7:229–241
Senft RL, Coughenour MB, Bailey DW, Rittenhouse LR, Sala OE, Swift DM (1987) Large herbivore foraging and ecological hierarchies. Bioscience 37:789–799
Shannon G, Page B, Duffy K, Slotow R (2006) African elephant home range and habitat selection in Pongola Game Reserve, South Africa. Afri Zool 41:37–44
Skarpe C, Bergström R, Bråten AL, Danell K (2000) Browsing in a heterogenuos savanna. Ecography 23:632–640
Slotow R, van Dyk G (2001) Role of delinquent young ‘orphan’ male elephants in high mortality of white rhinoceros in Pilansberg National Park, South Africa. Koedoe 44:85–94
Slotow R, van Dyk G, Poole J, Page B, Klocke A (2000) Older bull elephants control young males. Nature 408:425–426
Spaeth DF, Bowyer RT, Stephenson TR, Barboza PS (2004) Sexual segregation in moose Alces alces: an experimental manipulation of foraging behaviour. Wildl Biol 10:59–72
Spinage CA (1994) Elephants. T & AD Poyser, London
Stephens DW, Krebs JR (1986) Foraging theory. Princeton University Press, Princeton, NJ
Stokke S, du Toit J (2000) Sex and size related differences in the dry season feeding patterns of elephants in Chobe National Park, Botswana. Ecography 23:70–80
Stokke S, du Toit JT (2002) Sexual segregation in habitat use by elephants in Chobe National Park, Botswana. Afr J Ecol 40:360–371
du Toit JT (1990) Feeding-height stratification among African browsing ruminants. Afr J Ecol 28:55–61
Van Soest PJ (1996) Allometry and ecology of feeding behaviour and digestive capacity in herbivores: a review. Zoo Biol 15:455–479
Wittermeyer G, Douglas-Hamilton I, Getz WM (2005) The socioecology of elephants: analysis of the processes creating multitiered social structures. Anim Behav 69:1357–1371
Acknowledgments
Thanks to the owners and managers of the Pongola Game Reserve and Phinda Private Game Reserve, without whom this research would not have been possible. Our thanks also go to Heleen Druce for collecting the data in the PPGR and to Brad Carter and Mark Gillies for their invaluable assistance in PGR. This study was funded by the Amarula Elephant Research Programme, the National Research Foundation (GUN #:2053623), the University of KwaZulu-Natal and the Durban Institute of Technology. This study has been carried out in accordance with the current laws of South Africa.
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Shannon, G., Page, B.R., Duffy, K.J. et al. The role of foraging behaviour in the sexual segregation of the African elephant. Oecologia 150, 344–354 (2006). https://doi.org/10.1007/s00442-006-0521-1
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DOI: https://doi.org/10.1007/s00442-006-0521-1