Vocalization of Two Palaearctic Species of Hamster: Eversmann Hamster Allocricetulus eversmanni and Grey Hamster Cricetulus migratorius

This study compared the vocalization of two sympatrically occurring species of hamster: the Eversmann hamster Allocricetulus eversmann and the Grey hamster Cricetulus migratorius. The animals were tested in conspecific pairs for 5 min. Because of the high level of aggressiveness of both species, the hamsters were separated by a mesh partition, but they had olfactory, visual and acoustic contact. Female and male Eversmann hamsters vocalized more than those of Grey hamsters. This was expressed by emission of low-frequency calls as well as by ultrasounds. The difference in vocalization between the two species was also reflected in the basic structure of ultrasonic vocalizations. Grey hamster high-frequency (ultrasonic) pulses were longer and had larger bandwidths and lower minimum frequencies than Eversmann hamster calls. Within-species comparison of vocalization indicated that males of both species emitted fewer ultrasounds than females did. These differences could have an important role in communication within and between species living in the same area and preferring the same habitats.