Not speaking my language: playback experiments reveal early-orphaned human-reared adult cheetahs lack interest in species-specific vocalizations

Abstract Early adult models, particularly the mother, play an essential role in tuning perception to build the multimodal representation of species-specific social signals, especially in mammals. Therefore, early maternal loss adversely impacts social integration in mammals. Moreover, orphaned cheetahs may be subsequently human-reared, to an extent that depends upon the development stage at orphancy. In the present study, we hypothesized that the timing of maternal loss may influence orphaned cheetahs’ ability to build species-specific recognition, as this species exhibits a “two-stage” development: during the first two months after birth, cubs are hidden in a den while the mother hunts on her own, thereafter the cubs start following the mother and are in increasingly long contact with her. To test this hypothesis, we broadcasted unfamiliar human and cheetah voices to 25 captive adult cheetahs orphaned at one of these two stages and before the age of 6 months. Early-orphaned male cheetahs responded quicker, paid attention for longer, and displayed more activity changes in response to the human voice than the late-orphaned males, whereas early-orphaned females showed less interest in the cheetah voice than the late-orphaned females. Early-orphaned cheetahs were 5.6 times more likely to respond to a human voice than late-orphaned cheetahs. This study is the first to demonstrate a long-lasting difference caused by early-vs.-late-orphancy on acoustic perceptual development and reveals an experience-dependent perceptual plasticity that influences species-specific representation into adulthood that may underlie the reduced reproductive success observed in hand- versus mother-reared cheetahs.