• Inter-unit contests within a provisioned troop of Sichuan snub-nosed monkeys (Rhinopithecus roxellana) in the Qinling Mountains, China

      Zhao, Q.; Tan, Chia L.; (2010)
      ... In this study, we studied inter‐unit contests in a provisioned troop of Sichuan snub‐nosed monkeys (Rhinopithecus roxellana). We spent 368 hr in contact with 9 one‐male units sharing the same home range, during which we recorded 148 inter‐unit contests at a provisioning site. Inter‐unit contests always started as inter‐individual contests....
    • Regurgitation and reingestion in bonobos (Pan paniscus): Relationships between abnormal and social behavior

      Miller, Lance J.; Tobey, Jennifer R. (2012)
      Regurgitation and reingestion (R/R) is an abnormal behavior observed in great apes analogous to rumination syndrome in humans….The purpose of the current study was to examine R/R in 14 bonobos (Pan paniscus) at two zoological institutions. This included examining the relationships between R/R and other bonobo behaviors as well as the effect of a change in social groupings on R/R….
    • Reproductive competition and fecal testosterone in wild male giant pandas (Ailuropoda melanoleuca)

      Nie, Yonggang; Swaisgood, Ronald R.; Zhang, Zejun; Liu, Xiaobin; Wei, Fuwen (2012)
      ...Using global positioning system/very high frequency radiocollars to locate mating aggregations, we used behavioral observations and fecal testosterone assays to gain insight into male panda reproductive effort and strategies, and test theories relating to reproductive competition. Male pandas initially competed fiercely for access to females that were about to be fertile, but once male competitive status was determined, aggression rates declined....
    • Social context mediates testosterone's effect on snort acoustics in male hyrax songs

      Weissman, Yishai A.; Demartsev, Vlad; Ilany, Amiyaal; Barocas, Adi; Bar-Ziv, Einat; Geffen, Eli; Koren, Lee (2019)
      Testosterone affects physical and motivational states, both of which may strongly influence vocalization structure and acoustics. The loud complex calls (i.e., songs) of male rock hyraxes (Procavia capensis) are used as honest signals for advertising physical and social states. The snort, a low frequency, noisy element of the song, encodes information on the singer's age and social rank via harshness, as measured by jitter (i.e., acoustic frequency stability) and duration; suggesting that the snort concomitantly advertises both vocal stability and aggression. Our past findings revealed that testosterone levels are related to both vocal elements and social status of male hyraxes, suggesting that hormonal mechanisms mediate the motivation for aggressive and courtship behaviors. Here we examined whether long-term androgen levels are related to snort acoustics and song structure by comparing levels of testosterone in hair with acoustic and structural parameters. We found that songs performed by individuals with higher testosterone levels include more singing bouts and longer, smoother snorts, but only in those songs induced by external triggers. It is possible that hyraxes with higher levels of testosterone possess the ability to perform higher-quality singing, but only invest in situations of high social arousal and potential benefit. Surprisingly, in spontaneous songs, hyraxes with high testosterone were found to snort more harshly than low-testosterone males. The context dependent effects of high testosterone on snort acoustics suggest that the aggressive emotional arousal associated with testosterone is naturally reflected in the jittery hyrax snort, but that it can be masked by high-quality performance.
    • The effects of education programs on Atlantic bottlenose dolphin (Tursiops truncatus) behavior

      Miller, Lance J.; Mellen, J.; Greer, T.; Kuczaj, S.A. (2011)
      ...The present study examined the short-term effects of dolphin shows and interaction programmes on the behaviour of Atlantic bottlenose dolphins at six facilities. Rates of affiliative behaviour, aggressive behaviour, repetitive behaviour and percentage of time spent socialising were found to be unrelated to dolphin shows or interaction programmes....
    • The roles of competition and environmental heterogeneity in the maintenance of behavioral variation and covariation

      Dochtermann, Ned A.; Jenkins, Stephen H.; Swartz, Maryke J.; Hargett, Allison C. (2012)
      Many models of selection predict that populations will lose variation in traits that affect fitness. Nonetheless, phenotypic variation is commonly observed in natural populations. We tested the influences of competition and spatial heterogeneity on behavioral variation within and among populations of Merriam's kangaroo rats (Dipodomys merriami) and tested for the differential expression of trait correlations....