We romanticize the calls of birds and whales and ascribe meaning to the vocalizations of our pets. Yet most people don’t know that mice talk too, and that we would be wise to listen.
Mice vocalize at ultrasonic frequencies, above the threshold of human hearing. With special audio equipment, it is possible to hear what they would sound like if their vocalizations were brought down to an audible range. Here are two samples of mouse vocalizations, one chirpy and one whistle-like.
Scientists have found that male mice ‘sing’ to potential mates. These vocalizations are composed of syllables that form repeated phrases, a characteristic of song across species. Can you imagine these little guys singing love ballads on your kitchen floor?
The fact that mice vocalize and that these vocalizations are behaviorally relevant is not just fodder for trivia night. It may actually help us understand the causes of major psychiatric and neurological illnesses in humans.
Transgenic (a.k.a. mutant) mice are in widespread use in labs around the globe. Each strain of mutant mouse is designed with a specific change to their DNA. For example, the deletion of a specific gene from a strain’s DNA results in “knockout” mutant mice. By making the gene disappear and seeing what happens to the mice, we learn what that gene does. If the gene is related to disease in humans, we learn something about the disease. This method works more often than you might think, since more than 90 percent of the mouse genome is shared with humans.
Thank god for the remaining 10 percent. Shared DNA aside, we all know that mice and humans are very different, so it can be hard for scientists to tell whether abnormalities in the mouse are truly analogous to symptoms of human disease.
The problem is even tougher in studies of brain function and illness. How can we tell what a mouse does and doesn’t remember? Can mice have symptoms of schizophrenia, depression, or autism? Do they ever feel insecure and yearn for someone to love? Scientists have to put a lot of thought into answering questions like these.
I once attended a talk by Jacqueline Crawley, a neuroscientist at NIMH who wrote the book What’s Wrong With My Mouse? She pointed out that mouse vocalizations might serve as a model for human vocalizations. And since speech and social interaction are affected in several brain disorders, ‘listening’ to mutant mice could help us learn about the genes involved.
Crawley recently published an example of this kind of work: a study of vocalizations in a mutant mouse model of autism. Children with autism usually exhibit abnormal speech and social development. Crawley found that the vocalizations of the mutant mice were also abnormal. Kazow!
It’s too early to draw any real conclusions from this study, or to say that mouse vocalizations are truly analogous to human vocalizations. I’m sure more studies are in the works to find out.
In the meantime, let’s all do our part. If you find a mouse in your home, don’t just kill it. Wait and hear what it has to say.