Arcadi, A. C. (1996). Phrase structure of wild chimpanzee pant hoots: Patterns of production and interpopulation variability. American Journal of Primatology, 39, 159–178.
Bates, D., Maechler, M., Bolker, B., Walker, S., Christensen, R. H. B., Singmann, H., et al. (2016). lme4: Linear Mixed-Effects Models using ‘Eigen’ and S4 (Version 1.1–12).
Benítez, M. E., Le Roux, A., Fischer, J., Beehner, J. C. & Bergman, T. J. (2016). Acoustic and temporal variation in gelada (Theropithecus gelada) loud calls advertise male quality. International Journal of Primatology, 37, 568–585. https://doi.org/10.1007/s10764-016–9922–0
Boersma, P. (2001). Praat, a system for doing phonetics by computer. Glot International, 5, 341–345.
Clark, A. P. (1993). Rank differences in the production of vocalizations by wild chimpanzees as a function of social context. American Journal of Primatology, 31, 159–179. https://doi.org/10.1002/ajp.1350310302
Clutton-Brock, T. (2016). Reproductive competition among males. In Mammal Societies (pp. 427–466). Chichester: John Wiley & Sons.
Crockford, C. & Boesch, C. (2003). Context-specific calls in wild chimpanzees, Pan troglodytes verus: Analysis of barks. Animal Behaviour, 66, 115–125. https://doi.org/10.1006/anbe.2003.2166
Dobson, A. J. & Barnett, A. (2008). An Introduction to Generalized Linear Models. Boca Raton: Chapman and Hall/CRC.
East, M. L. & Hofer, H. (1991). Loud calling in a female-dominated mammalian society: II. Behavioural contexts and functions of whooping of spotted hyaenas, Crocuta crocuta. Animal Behaviour, 42, 651–669. https://doi.org/10.1016/S0003–3472(05)80247–7 Ey, E., Pfefferle, D. & Fischer, J. (2007). Do age- and sex-related variations reliably reflect body size in non-human primate vocalizations? A review. Primates, 48, 253–267. https://doi.org/10.1007/s10329-006–0033–y Fedurek, P., Slocombe, K. E., Enigk, D. K., Thompson, M. E., Wrangham, R. W. & Muller, M. N. (2016). The relationship between testosterone and long-distance calling in wild male chimpanzees. Behavioral Ecology and Sociobiology, 70, 659–672. https://doi.org/10.1007/s00265-016–2087–1 Fischer, J., Kitchen, D. M., Seyfarth, R. M. & Cheney, D. L. (2004). Baboon loud calls advertise male quality: Acoustic features and their relation to rank, age, and exhaustion. Behavioral Ecology and Sociobiology, 56, 140–148. https://doi.org/10.1007/s00265-003–0739–4 Fitch, W. T. (1997). Vocal tract length and formant frequency dispersion correlate with body size in rhesus macaques. Journal of the Acoustical Society of America, 102, 1213–1222. https://doi.org/10.1121/1.421048
Fitch, W. T. & Hauser, M. D. (2003). Unpacking ‘honesty’: Vertebrate vocal production and the evolution of acoustic signals. In Simmons, A. M., Fay, R. R. & Popper, A. N. (eds.), Acoustic Communication (pp. 65–137). New York: Springer.
Forstmeier, W. & Schielzeth, H. (2011). Cryptic multiple hypotheses testing in linear models: Overestimated effect sizes and the winner’s curse. Behavioral Ecology and Sociobiology, 65, 47–55. https://doi.org/10.1007/s00265-010–1038–5
Grawunder, S., Crockford, C., Clay, Z., Kalan, A. K., Stevens, J. M., Stoessel, A., et al. (2018). Higher fundamental frequency in bonobos is explained by larynx morphology. Current Biology, 28, R1188–R1189.
Hill, K., Boesch, C., Goodall, J., Pusey, A. E., Williams, J. & Wrangham, R. W. (2001). Mortality rates among wild chimpanzees. Journal of Human Evolution, 40, 437–450. https://doi.org/10.1006/jhev.2001.0469
Jungers, W. L. & Susman, R. L. (1984). Body size and skeletal allometry in African apes. In Susman, R. L. (ed.), The Pygmy Chimpanzee: Evolutionary Biology and Behavior (pp. 131–177). New York: Plenum Press.
Kalan, A. K. & Boesch, C. (2015). Audience effects in chimpanzee food calls and their potential for recruiting others. Behavioral Ecology and Sociobiology, 69, 1701–1712. https://doi.org/10.1007/s00265-015–1982–1 Kitchen, D. M., Seyfarth, R. M., Fischer, J. & Cheney, D. L. (2003). Loud calls as indicators of dominance in male baboons (Papio cynocephalus ursinus). Behavioral Ecology and Sociobiology, 53, 374–384. https://doi.org/10.1007/s00265-003–0588–1
McClelland, B. E., Wilczynski, W. & Ryan, M. J. (1996). Correlations between call characteristics and morphology in male cricket frogs (Acris crepitans). Journal of Experimental Biology, 199, 1907–1919.
Muller, M. N. & Mitani, J. C. (2005). Conflict and cooperation in wild chimpanzees. Advances in the Study of Behaviour, 35, 275–331.
Neumann, C., Assahad, G., Hammerschmidt, K., Perwitasari-Farajallah, D. & Engelhardt, A. (2010). Loud calls in male crested macaques, Macaca nigra: A signal of dominance in a tolerant species. Animal Behaviour, 79, 187–193. https://doi.org/10.1016/j.anbehav.2009.10.026 Pfefferle, D., West, P. M., Grinnell, J., Packer, C. & Fischer, J. (2007). Do acoustic features of lion, Panthera leo, roars reflect sex and male condition? Journal of the Acoustical Society of America, 121, 3947–3953. https://doi.org/10.1121/1.2722507 Pitcher, B. J., Briefer, E. F., Vannoni, E. & McElligott, A. G. (2014). Fallow bucks attend to vocal cues of motivation and fatigue. Behavioral Ecology, 25, 392–401. https://doi.org/10.1093/beheco/art131 Potter, D. M. & Griffiths, D. J. (2006). Omnibus permutation tests of the overall null hypothesis in datasets with many covariates. Journal of Biopharmaceutical Statistics, 16, 327–341. https://doi.org/10.1080/10543400600609585 Puts, D. A., Hill, A. K., Bailey, D. H., Walker, R. S., Rendall, D., Wheatley, J. R., et al. (2016). Sexual selection on male vocal fundamental frequency in humans and other anthropoids. Proceedings of the Royal Society B, 283(1829). https://doi.org/10.1098/rspb.2015.2830
R Core Team. (2016). R: A Language and Environment for Statistical Computing. Vienna: R Foundation for Statistical Computing.
Reby, D. & McComb, K. (2003). Anatomical constraints generate honesty: Acoustic cues to age and weight in the roars of red deer stags. Animal Behaviour, 65, 519–530. https://doi.org/10.1006/anbe.2003.2078 Reno, P. L., Meindl, R. S., McCollum, M. A. & Lovejoy, C. O. (2003). Sexual dimorphism in Australopithecus afarensis was similar to that of modern humans. Proceedings of the National Academy of Sciences of the United States of America, 100, 9404–9409. https://doi.org/10.1073/Proceedings of the National Academy of Sciences of the United States of America.1133180100
Searcy, W. A. & Andersson, M. (1986). Sexual selection and the evolution of song. Annual Review of Ecology and Systematics, 17, 507–533.