Rodents With Rhythm Make The Best Dads

Male rock hyraxes with the best rhythm in courtship songs make for the best mating partners, say researchers.

The rodent-like mammals are known to woo females with tunes designed to arouse. Researchers now believe that male hyraxes that sing more frequently and with a stronger rhythm are likely to have more surviving offspring.

Scientists from Bar-Ilan University’s Mina and Everard Goodman Faculty of Life Sciences observed the daily morning activity of hyrax communities between 2002 and 2013 at the Ein Gedi Nature Reserve near the Dead Sea. They captured information about the hyrax’s location, behaviors, and vocalizations.

Genetic information for each hyrax was then analyzed in the lab alongside audio recordings. The researchers suggest that rhythm can actually indicate health and suitability as mates, as physiological ailments may 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 individuals living in proximity sing more similarly to each other.

“They tend to sing in crescendo (getting louder as the song progresses) and reach peak complexity towards the end of their songs, maybe to keep the audience engaged and listening to the signals.

“We have been studying hyraxes for the past 20 years and have previously found several patterns in their songs that are common features of human language and music.”

Rhythm has now been shown to act as an advertisement for individual quality in some species, while in others it helps in coordinating signals from different individuals within a group. However, it is not yet known if different rhythmic patterns are used for these two different functions.

The findings were published in the British Ecological Society Journal of Animal Ecology.