Singing Mice Protect Their Turf With High-Pitched Tunes

Sep. 26, 2013 — Two species of tawny brown singing mice that live deep in the mountain cloud forests of Costa Rica and Panama set their boundaries by emitting high-pitched trills, researchers at The University of Texas at Austin have discovered.

Although males of both the Alston's singing mouse (Scotinomys teguina) and Chiriqui singing mouse (S. xerampelinus) sing to attract mates and repel rivals within their respective species, the findings show for the first time that communication is being used to create geographic boundaries between species.

In this case, the smaller Alston's mouse steers clear of its larger cousin, the Chiriqui.

"Most people are puzzled by the existence of singing mice, but in reality many rodents produce complex vocalizations, including mice, rats and even pet hamsters," said Bret Pasch, a postdoctoral fellow in the Department of Integrative Biology and lead author on the paper, which was published online in The American Naturalist. "Often they're high-pitched and above the range of human hearing."

Both singing mouse species produce vocalizations that are barely audible to humans. Alston's singing mice are smaller and more submissive than Chiriqui singing mice, and they have longer, higher-pitched songs than their larger cousins.

"Songs consist of a set of rapidly repeated notes, called trills," said Pasch. "Notes are produced each time an animal opens and closes its tiny mouth, roughly 15 times per second."

The two mouse species share similar diets and live in similar forest habitats. Such overlap in lifestyle often leads to conflict.

"A long-standing question in biology is why some animals are found in particular places and not others. What factors govern the distribution of species across space?" said Pasch.

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Singing Mice Show Signs of Learning

ScienceDaily (Oct. 10, 2012) — Guys who imitate Luciano Pavarotti or Justin Bieber to get the girls aren't alone. Male mice may do a similar trick, matching the pitch of other males' ultrasonic serenades. The mice also have certain brain features, somewhat similar to humans and song-learning birds, which they may use to change their sounds, according to a new study.

"We are claiming that mice have limited versions of the brain and behavior traits for vocal learning that are found in humans for learning speech and in birds for learning song," said Duke neurobiologist Erich Jarvis, who oversaw the study. The results appear Oct. 10 in PLOS ONE and are further described in a review article in Brain and Language.

The discovery contradicts scientists' 60-year-old assumption that mice do not have vocal learning traits at all. "If we're not wrong, these findings will be a big boost to scientists studying diseases like autism and anxiety disorders," said Jarvis, who is a Howard Hughes Medical Institute investigator. "The researchers who use mouse models of the vocal communication effects of these diseases will finally know the brain system that controls the mice's vocalizations."

Read on:  http://www.sciencedaily.com/releases/2012/10/121010172128.htm

Of Mice and Melodies: Research On Language Gene Seeks to Uncover the Origins of the Singing Mouse

ScienceDaily (Aug. 10, 2012) — Singing mice (scotinomys teguina) are not your average lab rats. Their fur is tawny brown instead of the common white albino strain; they hail from the tropical cloud forests in the mountains of Costa Rica; and, as their name hints, they use song to communicate.

University of Texas at Austin researcher Steven Phelps is examining these unconventional rodents to gain insights into the genes that contribute to the unique singing behavior -- information that could help scientists understand and identify genes that affect language in humans.

"We can choose any number of traits to study but we try and choose traits that are not only interesting for their own sake but also have some biomedical relevance," said Phelps. "We take advantage of the unique property of the species."

The song of the singing mouse song is a rapid-fire string of high-pitched chirps called trills used mostly used by males in dominance displays and to attract mates. Up to 20 chirps are squeaked out per second, sounding similar to birdsong to untrained ears. But unlike birds, the mice generally stick to a song made up of only a single note.

"They sound kind of soft to human ears, but if you slow them down by about three-fold they are pretty dramatic," said Phelps.

Continued:  http://www.sciencedaily.com/releases/2012/08/120810193755.htm