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Male mice sing songs of love
01 Nov 2005
Male mice serenade females with ultrasonic love songs, a U.S. study had found.
Birds, insects and frogs commonly sing during courtship but until now, the only mammals known to croon have been people, bats and cetaceans such as whales and dolphins.
Timothy Holy, assistant professor of neurobiology
anatomy at Washington University School of Medicine,
holds a male lab mouse.
Scientists realized decades ago that male mice emit squeaks too high-pitched for humans to hear when they encounter female mice or their urine. However, the cries could have been random.
When a team from Washington University in St. Louis, Mo., analyzed the vocalizations, they found that male mice were actually repeatedly producing a series of differently-pitched "chirp-like" syllables
-- similar to bird songs.
Timothy Holy and Zhongsheng Guo of the university's School of Medicine exposed male mice to cotton swabs dipped in mouse urine ripe with pheromones, the chemical signals often linked to mating.
After finding that male mice responded to the females' urine, they recorded the vocalizations and played them back more slowly or at a lower pitch audible to humans.
They found the mice produced syllables of different pitches and durations rapidly (about 10 syllables per second), repeating the same "tune" after periods of silence.
Each of the mice sang a unique tune, said the scientists, who published details of their study on Nov. 1 in the scientific journal Public Library of Science Biology.
"The richness and diversity of mouse song appears to approach that of many songbirds," writes Holy, the study's lead author and an assistant professor of neurobiology and anatomy.