Both familiarity and kinship influence odour discrimination by females in a highly social African ground squirrel

Kin recognition can be important in species where inbreeding avoidance or nepotism (favouritism towards kin) rely on identifying kin, particularly in species with alloparental care. The mechanisms that facilitate kin discrimination, where recognition is determined through cues that correlate with relatedness, usually include either prior association (familiarity) or phenotype matching or both. Odour is an important cue used in a number of mammalian species to discern kin, particularly the ground-dwelling squirrels. Cape ground squirrels, Xerus inauris, are a cooperative-breeding species, living in tight-knit family groups. However, group fission, promiscuity and the large home ranges of breeding males result in a high variance in relatedness both within and among social groups, making them a good species to investigate kin discrimination. We examined whether females are capable of discriminating between the odours of familiar versus unfamiliar females that varied in their relatedness to the focal female using odour experiments. Overall, the average duration of sniffing of the odours of familiar and unfamiliar females did not differ. Similarly, females did not adjust their sniff duration relative to the degree of relatedness of familiar females. However, females appeared to discriminate by the degree of relatedness of unfamiliar (stranger) females, spending longer sniffing odours from females that were not related to them. Thus, females were capable of discriminating the degree of relatedness from odour but they did not do so within their family group. We conclude that Cape ground squirrels are able to discriminate kin. However, whether females in this facultative cooperative breeder use the degree of relatedness in direct social interactions and nepotistic behaviours remains to be investigated.Grants from the Natural Sciences and Engineering Research Council of Canada Discovery program (no. 04362 ), the University of Manitoba Field Work Support program and the Canadian Foundation of Innovation to J.M.W. and a University of Manitoba Faculty of Science Undergraduate Student Research Award to A.A.http://www.elsevier.com/locate/anbehav2020-02-01hj2019Mammal Research InstituteZoology and Entomolog