ProjectFactors influencing Vocal tract length and formant frequency in rutting male reindeer, and implication for sexual selection
A constantly growing and evolving field, acoustic studies seek to delineate both quantitative and qualitative data from the subject’s vocal recordings. Generalized, more recent advances in the theory of source-filtering have allowed for the decomposition of acoustics structures of vocal signals according to their mode of reproduction. Within caribou/reindeer (Rangifer tarandus), studies have revealed that particular acoustic characteristics can reliably indicate the quality of the male, such as body size, and that grunts also play a role in sexual selection. As a herding, polygamous species with an active autumn rutting period, males have evolved and developed a series of distinct calls for female herding and rival male antagonization. However, as acoustic profiling techniques are relatively nascent, there is still much to study within the field. To study the structure and composition of the rutting calls, I will be studying a semi-domesticated caribou population at the Kutuharju Field Reindeer Research Station in Kaamanen, Finland during rutting periods in early October. For most of the year, excluding calving and rutting periods, the herd is free-ranging, however, each individual is marked with collars. As a result, rearing and mating information is known, and further ecological and behavioural information is provided by the Finnish Reindeer Herders Association. For my project, vocalization information will be collected with audio recorders during the October ruts. Group composition (identities and numbers of females and males) and vocalization context (herding females or antagonizing opposing males) will also be noted to give the vocalization context and accompanying data. Consequently, I will be trying to elucidate how physical factors of caribou affect their rutting vocalizations.