Washington, September 18 : Researchers at the University of Zurich in Switzerland have found that male fallow deer's groans during the breeding season reveal their status and size, and the information is exploited by females to chose mates.
The researchers say that larger males have higher social status, and are preferentially chosen by females for mating.
During a study, they observed that higher-ranking males produced groans with lower minimum fundamental frequencies and to a lesser extent, with lower dispersion of formant frequencies that result from filtering of vocalizations in the vocal tract.
Larger males were also found to produce groans with lower formant frequencies and lower formant dispersion.
The researchers aid that dominance status was the factor most strongly related to mating success, with higher-ranking males having higher mating success.
Based on their observations, they came to the conclusion that the acoustic parameters were probably indirectly related to male mating success through dominance status.
Similarly in humans, say the researchers, men with lower pitch voices are perceived as more dominant and have higher reproductive success due to greater access to mates.
They say: "Fundamental frequency and formant frequencies may therefore represent acoustic cues to male quality that have mainly evolved in response to male-male competition. Other aspects of male vocal behaviour, such as the long-term investment in vocal display, are also likely to influence female mate choice in fallow deer."
According to them, the findings of this study may help advance the understanding of the possible evolutionary mechanisms underlying the extraordinary diversity of male deer vocalizations, and in general the structure and functioning of vocal communication in mammals.