Vocal cues to male androgen levels in giant pandas

Abstract

Little is known about the potential of non-human mammal vocalizations to signal information on the hormonal status of the caller. In the current study, we used endocrine data and acoustic analyses to determine whether male giant panda bleats provide reliable information about the caller's current androgen levels. Our results revealed significant relationships between acoustic features of male giant panda bleats and the caller's faecal androgen metabolite concentrations. To our knowledge, this constitutes the first demonstration that the acoustic structure of a non-human mammal call has the potential to yield information about the caller's current androgen levels. We go on to discuss the anatomical basis for our findings and the potential functional relevance of signalling information on male androgen levels in giant panda sexual communication.

Minke whale acoustic behavior and multi-year seasonal and diel vocalization patterns in Massachusetts Bay, USA

“…This idea is further supported by structural differences between pulse trains recorded in SBNMS and those from the Caribbean, with the latter lasting about 20 s longer and exhibiting more than twice as many pulses per pulse train (Table 1; Mellinger et al 2000). A correlation between call duration and arousal state has been demonstrated in some mammal species (Rendall 2003, Charlton et al 2011. In several baleen whales only the males produce songs, which intensify during the breeding season and seem to play an important role in reproduction (e.g.…”

Giant pandas attend to androgen-related variation in male bleats

“…Specifically, we played back male giant panda bleats that had been re-synthesised to have high and low F0 modulation rates, simulating male callers with high and low androgen levels, respectively (Charlton et al 2011). High testosterone levels are associated with increased sperm quality (Minter and DeLiberto 2008), and may signal overall male quality because androgens are immunosuppressant and can only be produced at high levels by otherwise healthy individuals (Folstad and Karter 1992;Zahavi and Zahavi 1997).…”

“…In addition, the rate of fundamental frequency (F0) modulation in male giant panda bleats is positively correlated to male androgen levels (Charlton et al 2011); raising the possibility that male and female giant pandas could also make use of this information in reproductive contexts. Charlton et al (2011) suggest that higher androgen levels could increase vocal fold stiffness, by increasing the collagen/elastin ratio (Fischer and Swain 1980), leading to greater elastic recoil and higher potential rates of F0 modulation.…”

“…In addition, the rate of fundamental frequency (F0) modulation in male giant panda bleats is positively correlated to male androgen levels (Charlton et al 2011); raising the possibility that male and female giant pandas could also make use of this information in reproductive contexts. Charlton et al (2011) suggest that higher androgen levels could increase vocal fold stiffness, by increasing the collagen/elastin ratio (Fischer and Swain 1980), leading to greater elastic recoil and higher potential rates of F0 modulation. Furthermore, given that males with higher levels of testosterone (the primary androgen secreted by the testis) are typically more aggressive (Zielinski and Vandenbergh 1993;Gerald 2001) and preferred by females in mate choice contexts (for a review, see Clutton-Brock and McAuliffe 2009), acoustic features that signal male androgen levels may have utility in giant panda sexual communication for both intrasexual assessment and mate choice.…”

Vocalization as Potential Indicator of Animal's Welfare for Improving Animal Management and Productivity: A Review

“…shape, length and tension of the vocal tract. The source-filter theory has recently been applied to various species and revealed interesting links between vocalizations and the caller's anatomical or physiological attributes (Reby and McComb, 2003;Briefer et al, 2010; McElligott, 2011; Charlton et al, 2011). Various vocal parameters along with description that are most commonly used in mammals study are listed in Table 1.…”