Peer Reviewed Social Dominance and Male Breeding Success in Captive White-Tailed Deer RANDY W. DEYOUNG, 1 Department of Wildlife and Fisheries, Mississippi State University, Mississippi State, MS 39762, USA STEPHEN DEMARAIS, Department of Wildlife and Fisheries, Mississippi State University, Mississippi State, MS 39762, USA RODNEY L. HONEYCUTT, Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX 77843, USA KENNETH L. GEE, Samuel Roberts Noble Foundation, Allen, OK 78425, USA ROBERT A. GONZALES, Samuel Roberts Noble Foundation, Ardmore, OK 73402, USA Abstract Management strategies that incorporate the social behavior of wildlife may be more efficient in achieving population objectives. Our current knowledge of white-tailed deer (Odocoileus virginianus) social behaviors may not be adequate for application to management. Using captive white-tailed deer, we investigated the long-held assumption that relatively few dominant males sire most offspring and, thus, prevent subordinates from breeding. Although this assumption influences population predictions and management strategies, empirical studies of the relationship between dominance and male breeding success in deer are lacking. We determined male dominance rank and genetic paternity through 6 breeding trials. Although dominant males sired most offspring, subordinates sired offspring in 5 of 6 trials and multiple paternity (siring of offspring by 2 males) occurred in ;24% of compound litters. Further, male dominance ranks were not necessarily predictable or stable during the breeding season. This study indicates that the relationship between social dominance and male breeding success may be more complex than previously thought. Our findings also are consistent with recent studies of parentage in wild deer, providing additional evidence that social dominance does not necessarily equate to breeding success. Conceptual models of deer breeding behaviors should account for considerable individual heterogeneity among males in their ability to sire offspring. (WILDLIFE SOCIETY BULLETIN 34(1):131–136; 2006) Key words behavior, breeding success, Odocoileus virginianus, parentage, paternity, social behavior, white-tailed deer. Reliable knowledge of animal social behaviors may be used to increase the effectiveness of management strategies (e.g., Porter et al. 1991) and offer more realistic predictions of population responses to management actions (Co ˆte ´ 2003). Many authors have advocated an increased consideration of social behaviors in the management of wildlife (see Festa-Bianchet and Apollonio 2003), including white-tailed deer (Odocoileus virginianus; Porter et. al. 1991, Miller 1997, Miller and Ozoga 1997). However, the existing knowledge base on white-tailed deer social behaviors has been criticized as simplistic (Miller and Ozoga 1997), based on anecdotal evidence or a small number of visual observations. Therefore, the current state of knowledge regarding social behaviors may not be adequate to gauge effects of current management practices on or support the development of new management strategies for white-tailed deer. For instance, the breeding structure of white-tailed deer has been described as dominance-based (Hirth 1977, McCullough 1979, Marchinton and Hirth 1984). Among males, dominance and social rank often are associated with physical traits, such as age and body mass, with the top ranks in dominance hierarchies held by mature, large-bodied individuals (Townsend and Bailey 1981, Miller et al. 1987). Because physical maturity and maximum body mass in males are attained after 4 years of age (Sauer 1984, Strickland and Demarais 2000), this is presumably when males hold their maximum dominance ranks. A relatively few dominant males are assumed to sire most offspring in age-structured populations, while the reproductive performance of subdominants is thought to be suppressed through behavioral interactions (Hirth 1977, McCul- lough 1979, Marchinton and Hirth 1984, Miller and Ozoga 1997). The assumption of a dominance-based breeding hierarchy, where most offspring are sired by a few dominant males, is a central tenet of deer ecology and management, affecting both population predictions and management strategies. For instance, some degree of inbreeding is hypothesized to occur because a male may remain dominant in an area for several years, breeding within the same matriline (Nelson and Mech 1987). Estimates of breeding gender ratios disregard young males (,3 years of age) as unlikely to breed (Cronin et al. 1991). Changes in male age structure due to intense harvest are predicted to result in reduced in population fitness over extended time periods because dominance-based breeding becomes a scramble competition, allowing less-fit males to breed (Ozoga and Verme 1985, Miller and Ozoga 1997). Young males are assumed to invest few resources in reproductive efforts in the presence of physically mature males (Miller and Ozoga 1997). Finally, the recent increase in the intensive management of white-tailed deer (e.g., Demarais et al. 2002) has led some to recommend protecting mature large-antlered males as breeder bucks in an effort to increase population antler size, assuming these individuals will sire many offspring (see Rollins 1998). We contend that the importance of social dominance in the breeding success of white-tailed deer is questionable because this tenet is largely based on circumstantial evidence. Studies using genetic paternity assignment in populations of large mammals increasingly have revealed patterns of breeding success that differ from those based on visual observations (Pemberton et al. 1992, Amos et al. 1995, Hogg and Forbes 1997, Coltman et al. 1999, 1 E-mail: randall.deyoung@tamuk.edu 2 Present address: Caesar Kleberg Wildlife Research Institute, Texas A&M University-Kingsville, Kingsville, TX 78363, USA DeYoung et al.  White-Tailed Deer Breeding Success 131