Advertising sex and individual identity by long-distance chirps in wild-living mature cheetahs (Acinonyx jubatus)

Adult cheetahs (Acinonyx jubatus) use long-distance chirps for calling toward coalition partners (males), mates (both sexes), and cubs (females). Previously, these vocalizations were only investigated in captivity. This study estimates individual and sex-related acoustic variation of the long-distance chirps of 20 mature cheetahs (eight males and 12 females older than 4 years) in their natural habitats in Kenya. Male chirps were longer in duration and lower in the peak frequency and all fundamental frequency variables than female chirps. The average value for assignment of the chirps to correct sex with Discriminant Function Analysis (DFA) of 93.8% was significantly higher than by-chance level of 52.9%. The average value of correct assignment of the chirps to individual with DFA was 79.5%, which was significantly higher than the level by chance of 14.8%. For 10 cheetahs recorded twice with time space of one or 2 years, DFA showed high values of correct assignment of the chirps to individual for both years (91.4% in the first year and 83.9% in the second year of recording), but cross-validation of the chirps recorded in the second year by discriminant functions created for the chirps of the first year showed a dramatic decrease of correct assignment to the level expected by chance (27.2%). We discuss that long-distance chirps of wild mature cheetahs provide reliable cues to sex and may also encode caller individuality, although this is not stable over time.

Automated summary

Adult cheetahs use long-distance chirps to communicate with coalition partners, mates, and cubs. This study analyzed the acoustic variation of these vocalizations in 20 mature cheetahs in Kenya. Male chirps were longer and had lower frequencies than female chirps. The chirps also showed individual differences, but these were not consistent over time.