Tiny nocturnal lemurs recognize their dad's cries amid the other sounds of the nighttime Madagascar forests, a new study finds. The research is the first to show that solitary animals may avoid inbreeding by keeping an ear out for familiar voices.
Previous studies have found that animals living in complex social groups have no trouble recognizing their own kin's calls, particularly the sounds of maternal relatives. Even goat mamas keep a long-term memory for their baby's calls, according to a study published earlier this year.
But less is known about how animals recognize their father's calls, and the cries of the relatives on dad's side of the family. Likewise, researchers know very little about how solitary-living animals avoid inbreeding with dad's side of the family.
That's where the gray mouse lemur (Microcebus murinus) comes in. These cartoonishly cute lemurs are raised by their mothers without help from dad. When they grow up, they head out of the nest to forage on their own. But male lemurs' ranges are large, and they often overlap with that of their daughters', suggesting the primitive primates have evolved some way to avoid accidentally mating with a relative.
To find out how, researchers led by Arizona State University's Sharon Kessler played male mating calls and alarm cries for 10 adult female gray mouse lemurs housed at the University of Veterinary Medicine in Hannover, Germany. Each lemur heard her father's cries as well as an unrelated male's. The researchers recorded how attentive the lemurs were to each call. For example, an interested lemur might stare at or run over to the speaker playing the call. [ Image Gallery: Leaping Lemurs ]
The female lemurs paid equal attention to alarm calls from fathers and unrelated males, the researchers report in an upcoming issue of the journal BMC Ecology. But when it came to mating calls, lady lemurs perked up much more at unrelated male's calls. Compared to when they heard a father's cry, the lemurs approached the non-kin speakers faster, sooner and stayed longer looking for the source of the sound.
The take-away, Kessler and her colleagues wrote, is that recognizing dad's voice requires neither a big brain nor a complex social life. In fact, ability to recognize kin may have preceded complex social structures in evolutionary history.