Chemoreception and kin discrimination by neonate smooth snakes (Coronella austriaca)

The study of chemoreception by squamate reptiles has become integral to understanding many aspects of their behaviour. However, previous studies of snakes have concentrated on its importance in prey choice and few studies have examined its role in kin discrimination. We examined the role of chemoreception not only in prey selection by ingestively naïve neonate smooth snakes, but also as a mechanism for discrimination between kin. We tested the responses of neonate smooth snakes to cotton-tipped applicators labelled with odours of potential prey species and control substances, both before and after their natal shedding events. Neonates tested prior to their natal shedding event were able to discriminate between potential prey species and an odourless control but not between potential prey and a pungent control. In contrast, neonates tested after their natal shedding event showed a significantly increased tongue-flick response towards the scent of nonkin conspecifics, lizard (Anguis fragilis and Zootoca vivipara) and mammalian prey (Mus musculus) compared to that towards both pungent and odourless controls. However, scents of invertebrate prey species and kin, while eliciting more tongue-flicks than the odourless control, did not elicit more than the pungent control. The apparent ability of smooth snake neonates to differentiate between kin and nonkin using chemoreception was confirmed during ‘blind’ trials. The mechanism by which kin discrimination occurs is discussed.