Between-year vocal aging in female red deer (Cervus elaphus)

Abstract

Objectives: Studying animal vocal aging has potential implication in the feld of animal welfare and for modeling human voice aging. The objective was to examine, using a repeated measures approach, the between-year changes of weight, social discomfort score (bites of other hinds on hind pelt), body condition score (fat reserves) and acoustic variables of the nasal (closed-mouth) and the oral (open-mouth) contact calls produced by farmed red deer hinds (Cervus elaphus) toward their young. Results: Repeated measures ANOVA revealed that with an increase of hind age for 1 year, the acoustic variables of their nasal contact calls (the beginning and maximum fundamental frequencies, the depth of frequency modula‑ tion and the peak frequency) decreased, whereas in their oral contact calls only the end fundamental frequency decreased. Duration and power quartiles did not change in any call type. Body weight and body condition score increased between years, whereas discomfort score decreased. Results of this study revealed directly the short-term efects of aging on the acoustics of the nasal contact calls in the same hinds. This study also confrmed that elevated emotional arousal during emission of the oral contact masks the efects of aging on vocalization in female red deer