Male rock hyraxes with the best rhythm in courtship songs make the best mating partners, researchers say.
The rodent-like mammals are known to court females with tunes designed to excite them. Researchers now believe that male rock hyraxes that sing more frequently and with a stronger rhythm are likely to have more surviving offspring.
Scientists from the Mina and Everard Goodman Faculty of Life Sciences at Bar-Ilan University observed the daily morning activity of rock hyrax communities in the Ein Gedi nature reserve near the Dead Sea between 2002 and 2013. They collected information about the location, behavior and vocalizations of the rock hyrax.
Genetic information for each rock hyrax was then analyzed in the laboratory along with audio recordings. The researchers suggest that rhythm may actually indicate health and suitability as a mate, since physiological ailments can negatively affect their ability to produce precise and rhythmic calls.
dr Vlad Demartsev, who collected the data for this study, said: “Their songs have regional dialects, so people who live nearby sing more similarly.
“They tend to sing in crescendos (getting louder as the song progresses) and reach peak complexity towards the end of their songs, perhaps to keep the audience engaged and listening to the cues.
“We have studied rock hyraxes for the past 20 years and previously found several patterns in their songs that are common features of human speech and music.”
It has now been shown that rhythm acts as an advertisement for individual quality in some species, while in others it helps coordinate signals from different individuals within a group. However, it is not yet known whether different rhythmic patterns are used for these two distinct functions.
The findings were published in the British Ecological Society’s Journal of Animal Ecology.