• Female copulation calls vary with male ejaculation in captive olive baboons

      Vaglio, Stefano; Ducroix, Louise; Rodriguez Villanueva, Maria; Consiglio, Rosanna; Kim, Ayong Julia; Neilands, Patrick; Stucky, Kerstin; Lameira, Adriano R (Brill, 2020-08-11)
      Copulation calls are mating-associated vocalizations that are common in primates, with females vocalizing after copulation in several Old World monkeys and apes. Baboon females typically produce copulation calls that correlate with fertile phase. Calls are, thus, regarded as an upshot of cycle physiology and sexually selected calls. Here, we describe three captive troops of olive baboons wherein, against expectation, females suppressed vocalizing during copulations. Vaginal cytology, together with sexual swelling observations, confirmed that females experienced full receptive cycles. Ovulation did not affect vocal probability during sex, while copulation calls were predicted by male ejaculation just as in other Old World primate species. Results cast doubt on the existence of physiological triggers for baboon copulation calls. Social factors may instead play a larger role. Alterations in social structure (as typically observed in the wild) may be implemented strategically as captive enrichment in order to reveal how females in highly social primates change sexual strategies and, therefore, the use of their copulation calls.
    • Interactions with humans impose time constraints on urban-dwelling rhesus macaques (Macaca mulatta)

      Kaburu, Stefano S. K.; Beisner, Brianne; Balasubramaniam, Krishna N.; Marty, Pascal R; Bliss-Moreau, Eliza; Mohan, Lalit; Rattan, Sandeep K.; Arlet, Małgorzata E.; Atwill, Edward R.; McCowan, Brenda (Brill, 2019-06-28)
      Time is a valuable but limited resource, and animals’ survival depends on their ability to carefully manage the amount of time they allocate to each daily activity. While existing research has examined the ecological factors affecting animals’ activity budgets, the impact of anthropogenic factors on urban dwelling animals’ time budgets remains understudied. Here we collected data through focal animal sampling from three groups of rhesus macaques in Northern India to examine whether interactions with humans decrease macaques’ resting and social time (time constraints hypothesis), or whether, by contrast, foraging on anthropogenic food, that is potentially high in calories, leads macaques to spend more time resting and in social interactions (free time hypothesis). We found that macaques who interacted more frequently with people spent significantly less time resting and grooming, supporting the time constraints hypothesis. We argue that these time constraints are likely caused by the unpredictability of human behavior.