Robert Lishak, an associate professor in biological sciences who specializes in the study of animal behavior and acoustic behavior at Auburn University, is studying how squirrels communicate. He and his students analyzed acoustic signals that squirrels use to communicate with others of their species, as well as potential predators.
The team used both model and live cats that the squirrels perceived as potential predators. The squirrels made sounds to let the cats know that they were aware of their presence and to warn them to leave. Lishak and his students used software that turned squirrels’ barks into spectrograms, series of jagged lines that show the sounds’ duration and frequency.
According to Lishak, squirrels do not have a language per se. He said the sounds they make are signals that other squirrels naturally respond to, similar to the way a person would be startled by a loud noise.
Squirrels use sounds to communicate to each other during mating season and when caring for their young. They also use tooth chattering as an aggressive signal to warn other squirrels who are encroaching on their territory. The dominant structure in squirrel populations is adult male, adult female, young male, and young female. They also use sounds to alert each other when a predator is nearby and point their tails in the direction of a predator.
A study conducted by Richard Bicknell of the City of Palo Alto, California found that the vocalizations of squirrels range from 0.01 to 10 kilohertz in frequency. The sounds can range from a chirp to a long series of barks, screams, and purrs.