Spotted Hyena Research
Due to a remarkable suite of behavioral, anatomical, and endocrine characteristics, spotted hyenas (Crocuta crocuta) are uniquely interesting animals. In contrast to most other female mammals, female Crocuta are male-like in appearance, larger than males, and substantially more aggressive (Matthews 1939; Syzkman et al In press). Females are also socially dominant to males (Kruuk 1972), and our early work explored the ontogenetic development of female dominance (eg., Holekamp & Smale 1991, 1993; Smale et al 1993, 1995, 1997). Unlike other social carnivores, Crocuta live in large groups structured remarkably like those of certain old-world primates (Kruuk 1972; Frank 1986b; Mills 1990). Since our project began in 1988, we have focused on social development in Crocuta and found that many of the mechanisms mediating ontogenetic change in interactions among hyenas are similar to those seen in primates (Holekamp & Smale 1991,1998b; Holekamp et al 1997; Engh et al 2000; Smale et al 1995, 1999). Female dominance over males emerges in hyenas when males disperse, as they all invariably do in our study areas (Smale et al 1997; Van Horn et al 2003). In contrast to most male primates, male hyenas observed outside their natal areas behave submissively to each new conspecific encountered, regardless of its sex, age, or relative body size. As a result, males inevitably fall in social rank when they disperse, and suffer a substantial decline in their priority of access to food at ungulate kills (Holekamp & Smale 2000). However, despite these energetic costs of emigration, males seldom mate unless they disperse. Thus, from an adaptive perspective, males appear to 'trade' food for sex when they disperse from their natal clans (Engh et al 2002).
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To date, in addition to dissertations (Boydston; Engh; Szykman, Greene, Van Horn, Dloniak, Wahaj, Kolowski, Watts), several dozen papers from the ongoing hyena project have been published or are currently in press in peer-reviewed journals or books, and we usually have several others in review. Although we have been working with 5 different Crocuta clans for the past few years in two different Kenyan national parks, most of these papers were based on data collected from members of a single Crocuta study population, the Talek clan, that defends a territory in the Masai Mara National Reserve, Kenya (MMNR). Although our long-term work on Crocuta has emphasized behavioral development, we have also produced papers on endocrine mediation of behavior (Glickman et al 1993; Smale et al 1997; Holekamp & Smale 1998a, 2000a; Place et al 2002a; Holekamp & Sisk 2003; Dloniak et al 2004, 2005), hunting and feeding (Holekamp et al 1997a; Cooper et al 1999), conflict and cooperation (Smale et al 1995, 1999; Szykman et al 2003; Wahaj et al in review), demography (Frank et al 1995b; Holekamp & Smale 1995), reproductive biology (Holekamp et al 1996, 1999c; Holekamp & Smale 1990, 2000; Szykman et al in review), serology (Alexander et al 1994; 1995; Harrison et al 2004), parasitology (Engh et al 2003), taphonomy (Cooper et al 2005), space utilization (Holekamp et al 1997b, 2000; Boydston et al 2001, 2005), reconciliation (Wahaj et al 2001; Wahaj & Holekamp 2003), mate choice (Engh et al 2002; Szykman et al 2001), genetics (Libants et al 2000; Van Horn et al 2004b), conservation (Holekamp & Smale 1992; Boydston et al 2003a,b; Kolowski & Holekamp in review), and cognition (Holekamp et al 1999a, 2000; Wahaj et al 2001;Wahaj & Holekamp 2003; Engh & Holekamp 2003; Holekamp & Engh 2002; Engh et al 1999, 2005; Barrett et al in review).
Training of young scientists is considered an important mission in this laboratory. Since our hyena research began in 1988, 51 undergraduates, 43 graduate students, and 4 postdocs have been trained with NSF funds, including 13 Kenyans and 66 women. In addition to training Kenyan graduate students, our NSF funds are used to educate Kenyan grade-school children; MSU graduate students living at our research camp devote one morning each week to teaching Masai children in the two local elementary schools about their wildlife and the value of its conservation.
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