The roosting behavior of the big fruit-eating bat, Artibeus lituratus (Phyllostomidae, Stenodermatinae) in an Andean region of Venezuela is described. Sixty-four video recordings made at three separate foliage roosts during 1 year showed that group size varied between two and 14 individuals. One male was regularly observed roosting with more females than others, and this male was associated with the highest quality roost, defined here as the highest, most structurally stable, and least disturbed. Males invariably occupied exclusive roosts during the study, whereas females frequently moved among adjacent roosts. The high roost fidelity of males appears to be related to the defense of the highest quality roosts. Because females were observed roosting with each of the three males present at the study site, female groups were considered unstable. We suggest that shuttling movements of individuals may reflect a commonly observed adaptation of foliage roosting bats related to the avoidance of predators and/or parasites. The type of male-female association observed in A. lituratus is consistent with a resource defense polygyny hypothesis.

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Sexual dimorphism is the condition in which males and females of the same species are easily distinguished by specific traits (secondary sex characteristics), often related to body size, colour patterns, weapons, and ornaments. Males of many mammal species tend to be larger or more ornamented than females, and these characteristics tend to be more pronounced in polygynous, diurnal, and open‐habitat species. Bats have long been considered a largely non‐sexually dimorphic group due to lack of conspicuous differences in body size and other cranial and skeletal characters. However, bats, like many mammals, exhibit a diverse array of soft‐tissue integumentary glands and non‐glandular odour‐producing structures with intense odorous substances that have not been thoroughly investigated, although postulated functions include facilitating mate selection in their generally polygynous associations. To date, there has been no systematic assessment of the occurrence or expression of sexually dimorphic traits in bats, many of which show intriguing sexual dimorphism in soft tissue, and most of which involve intense odours. In this study, we review evidence of integumentary glands and non‐glandular odour‐producing structures known in bats, as a first step towards identifying future research pathways to study sexual dimorphism in bats. Highly variable glands and non‐glandular odour‐producing structures have been noticed in ten different regions of the body, but are most frequently found on the head and the ventral region of the neck. They have been described in nearly 9% of bat species and in 70% of 21 extant bat families. Our review, based on extremely scattered and unevenly detailed literature, unveils the extraordinary sexual dimorphism that has been observed in Chiroptera to date, identifying not only target body parts where sexually dimorphic traits are likely to be found, but also critical avenues for future investigation and discoveries, and stressing the importance of the timing of secondary sexual trait observations, behavioural studies, and chemical analyses.