Conradt L
Large Animal Research Group, Department of Zoology, Cambridge, UK.
Proc Biol Sci. 1998 Jul 22;265(1403):1359-63. doi: 10.1098/rspb.1998.0442.
In many sexually dimorphic mammal species, the sexes live outside the mating season in separate social groups ('social segregation'). Social segregation occurs in a wide range of environmental conditions, but its cause in unknown. I suggest that social segregation is caused by a lower level of activity synchrony between individuals in mixed-sex groups than in single-sex groups, owing to sex differences in activity rhythm. As a consequence, mixed-sex groups are more likely to break up than single-sex groups, resulting in a predominance of single-sex groups at equilibrium. To test this hypothesis in red deer (Cervus elaphus L.), I developed an index of activity synchronization and showed that deer in mixed-sex groups were significantly less synchronized in their activity than deer in single-sex groups. Thus, low intersexual synchrony in activity can lead to social segregation. However, a lower level of intrasexual (female-female and male-male) activity synchrony within mixed-sex than within single-sex groups implies that additional factors (other than sex differences in foraging rhythm) contribute to the higher degree of instability of mixed-sex groups.
在许多具有两性差异的哺乳动物物种中，两性在交配季节之外生活在不同的社会群体中（“社会隔离”）。社会隔离在广泛的环境条件下都会发生，但其原因尚不清楚。我认为，由于活动节奏的性别差异，混合性别群体中个体之间的活动同步性低于单一性别群体，导致了社会隔离。因此，混合性别群体比单一性别群体更有可能解体，从而在平衡状态下单一性别群体占主导地位。为了在马鹿（Cervus elaphus L.）中验证这一假设，我制定了一个活动同步指数，并表明混合性别群体中的鹿在活动上的同步性明显低于单一性别群体中的鹿。因此，两性之间活动同步性低会导致社会隔离。然而，混合性别群体中同性（雌性与雌性、雄性与雄性）活动同步性低于单一性别群体，这意味着其他因素（除了觅食节奏的性别差异）导致了混合性别群体更高程度的不稳定性。
