Sexually Dimorphic Dispersal in Mammals: Patterns, Causes, and Consequences

Smale, Laura; Nunes, Scott; Holekamp, Kay E.

doi:10.1016/s0065-3454(08)60380-0

Cited by 119 publications

(128 citation statements)

References 170 publications

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“…Female spotted hyenas are physiologically competent to breed after 24 months of age, but first parturition usually occurs in the third or fourth year of life; the timing of first parturition varies greatly with rank [16,23]. Female hyenas are philopatric, whereas nearly all males emigrate and join neighbouring clans after puberty [29,30]. Spotted hyenas live up to 19 years in the wild [31].…”

Section: Methodsmentioning

confidence: 99%

Lifetime selection on a hypoallometric size trait in the spotted hyena

2011

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Size-related traits are common targets of natural selection, yet there is a relative paucity of data on selection among mammals, particularly from studies measuring lifetime reproductive success (LRS). We present the first phenotypic selection analysis using LRS on size-related traits in a large terrestrial carnivore, the spotted hyena, which displays a rare pattern of female-biased sexual size dimorphism (SSD). Using path analysis, we investigate the operation of selection to address hypotheses proposed to explain SSD in spotted hyenas. Ideal size measures are elusive, and allometric variation often obfuscates interpretation of size proxies. We adopt a novel approach integrating two common methods of assessing size, and demonstrate lifetime selection on sizerelated traits that scale hypoallometrically with overall body size. Our data support selection on hypoallometric traits in hyenas, but not on traits exhibiting isometric or hyperallometric scaling relationships, or on commonly used measures of overall body size. Our results represent the first estimate of lifetime selection on a large carnivore, and suggest a possible route for maintenance of female-biased SSD in spotted hyenas. Finally, our results highlight the importance of choosing appropriate measures when estimating animal body size, and suggest caution in interpreting selection on size-related traits as selection on size itself.

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Section: Methodsmentioning

confidence: 99%

Lifetime selection on a hypoallometric size trait in the spotted hyena

2011

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“…Adult male whooping potentially advertises a male's presence in the territory to both prospective mates and male competitors (Mills, 1990). Adult immigrant males queue for social status in a linear dominance hierarchy such that a male's position in the hierarchy is determined by the length of time he has spent in the clan, relative to the tenures of other adult male clanmates (Smale et al, 1997;East & Hofer, 2001). For immigrant male spotted hyenas, length of residence in the clan has a large positive effect on reproductive success (Engh et al, 2002).…”

Section: Effect Of Call Context On Call Structure and Effects Of Calmentioning

confidence: 99%

Sources of variation in the long-distance vocalizations of spotted hyenas

Theis

Greene

Benson‐Amram

et al. 2007

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SummaryIt has long been recognized that vocal signals communicate information about the age, sex and affective state of callers. However, the mechanisms by which these types of information are communicated are less well understood. Here we investigated variation in the acoustic properties of the long-distance vocalizations, called 'whoops', emitted by free-living spotted hyenas, Crocuta crocuta. Specifically we investigated whether the fundamental frequency, length and rate of whoops provide information about the caller's age, sex and/or level of arousal. We determined the latter by contrasting whoops emitted spontaneously with whoops emitted during periods of social excitement, when callers typically also exhibited visual signals associated with heightened arousal. We found that the minimum fundamental frequency of a whoop provides reliable information about the caller's general age and, for adult callers, information about sex as well. The vast majority of adult male whoop bouts were emitted spontaneously, but juveniles and adult females produced many of their bouts during periods of social excitement. Although context did not significantly affect the whoop bouts of adult females, juvenile bouts emitted during social excitement had higher maximum fundamental frequencies, greater proportions of asymmetric whoop subtypes, and reduced inter-whoop intervals. By reducing the inter-whoop intervals of bouts, juvenile hyenas significantly increased the likelihood that conspecifics would respond to whoops by approaching the caller or its social companion. Peak fundamental frequency and the relative abundance of whoop subtypes did not appreciably affect response. We discuss the potential functions of whooping by juvenile and adult hyenas in light of these findings.

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“…Our understanding of dispersal patterns in animals is ever increasing, especially with respect to sex differences in dispersal probability and distance (Clutton-Brock & Sheldon, 2010) and the proximate and ultimate explanations for dispersal (Johnson & Gaines, 1990;Smale et al, 1997). However, for long-lived, social species like primates it is rare to have data on the events before and after dispersal (but see: Gould, 2006;Ekernas & Cords, 2007;Stoinski et al, 2009) or long-term life history information for the dispersing sex throughout more than one transfer (but see Sussman, 1992;Alberts & Altmann, 1995;Okamoto et al, 2000;Jack & Fedigan, 2004a,b).…”

Section: Introductionmentioning

confidence: 99%

Dispersal in male ursine colobus monkeys (Colobus vellerosus): influence of age, rank and contact with other groups on dispersal decisions

Teichroeb

Wikberg

Sicotte

2011

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SummaryDispersal is male-biased in ursine colobus monkeys (Colobus vellerosus), although female dispersal also occurs (Teichroeb et al., 2009). Here we describe the process of male dispersal and its connection with between-group encounters (BGEs, N = 444) and male incursions (when males left their group and approached within 50 m of another group; N = 128) at the Boabeng-Fiema Monkey Sanctuary in central Ghana. Through BGEs and incursions, particularly those with non-aggressive interactions between individuals in different groups (BGEs, N = 17; incursions, N = 4), males could probably assess other groups for dispersal opportunities. There was a trend for males to perform incursions more frequently before emigrating voluntarily than involuntarily. Incursions were often performed towards the group that the male eventually transferred to. Incursions by alpha males were temporally shorter and more aggressive than those by non-alpha males. We suggest that non-alpha males used incursions to assess other groups for breeding or dispersal opportunities, whereas alpha males performed incursions mainly to convey information about their quality to neighbouring males and females. Male emigrations/disappearances (natal N = 20, secondary N = 43, unknown N = 9) and immigrations (N = 62) were recorded for seven groups during ten years (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010). Alpha males always emigrated involuntarily. Parallel emigration and immigration occurred. Males often immigrated into groups with a more favourable adult male/adult female ratio and improved their rank, both of which likely increased their mating opportunities. The most fitting ultimate explanation for both natal and secondary male dispersal in this population was the intrasexual competition for mates hypothesis, as males of all ages appeared to emigrate to improve their reproductive opportunities.

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Sexually Dimorphic Dispersal in Mammals: Patterns, Causes, and Consequences

Cited by 119 publications

References 170 publications

Lifetime selection on a hypoallometric size trait in the spotted hyena

Lifetime selection on a hypoallometric size trait in the spotted hyena

Sources of variation in the long-distance vocalizations of spotted hyenas

Dispersal in male ursine colobus monkeys (Colobus vellerosus): influence of age, rank and contact with other groups on dispersal decisions

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