Frequency Characteristics in Animal Species Typically Used in Laryngeal Research: An Exploratory Investigation

Laryngeal research is typically conducted on animal species that have similar features to the human larynx, yet little is known of the frequency characteristics of those animals. This study examines frequency characteristics of dog, cat, pig, and sheep across emotional communication events.

Prospective study.

Acoustic data were gathered in domestic environment, with fundamental frequency (f_o) computation of vocalization during happy, distress, and food request activities.

Dogs demonstrated reduced f_o range and reduced vocalization as a factor of age (18 semitones for adult male dog, three semitones for aged male dog). When two barks were present, the second bark was typically shorter in length and had a higher f_o. Male cat was observed to be more talkative and exhibited a much higher purr f_o than his female housemate. Cat purr was varied by sex between the typical 25 Hz and a significantly higher f_o, consistent with literature on use of cry-purr by some cats. Lambs exhibited phonation breaks, and an overall frequency range of 28 semitones in lambs compared with 49 semitones for mature sheep. Piglets exhibited f_o range of 44 semitones with higher f_o with distress and lowest f_o for grunting.

Aged animals followed similar phonatory patterns of humans, with change of f_o for communication need. The male cat was found to purr differently from female cats. Pigs and cats may have nonlaryngeal source signal coupling. Animal phonation changes with emotion. Observed f_o patterns may improve interpretation of phonation among laboratory animals in laryngeal research.