The findings, published recently in the journal Animal Behavior, present some of the most detailed information to date on squirrel vocalizations, which the researchers now believe constitute a complex language that is unique to the animals.
The team of zoologists focused their analysis on alarm calls of the Richardson's ground squirrel, Spermophilus richardsonii, which is the most common ground squirrel in Canada.
Squirrels often communicate with whistles, chirps and chucks, which sound like the word "chuck." Whistles and chirps resemble the sounds that many birds make.
"A chuck is a short duration trailing element, which when added to the end of a syllable, harshens the offset of a call so that it punctuates the end of the syllable with a click," explained James Hare, one of the study's authors. [Sorta like the 'click' of the safety coming off?]
"The squirrel whistles and chirps are roughly equivalent to those of birds, with a whistle having a more or less constant pitch and a chirp decreasing in pitch over its duration."
Hare and his team coaxed squirrels to emit alarm calls by tossing a tan-colored brimmed hat in front of the animals. The hat mimics a bird or animal predator in color and can move low and fast. [Note to self: don't throw hats at squirrels before loosing a round.]
"In effect then, whistles that incorporate chucks say 'there's a predator of moderate threat that's here,' whistles without chucks say 'there's a predator of seemingly moderate threat around here somewhere,' while chirps that in nature don't incorporate chucks say, "I'm ducking for cover here because there's an immediate danger,'" Hare told Discovery News.
Hare and his colleagues believe such sounds are part of a sophisticated language that he said "likely evolved just as all other communication systems have: by chance association of certain cues with significant events at first and selection favoring individuals who detected and responded appropriately to the broadcast of such cues." [Darwin, again. Next they'll tell us that the chirps and chucks are Indo-European in origin and may not apply to Far Eastern
Although squirrels risk their lives when they call out to warn others of threats, Hare said other squirrels might admire this behavior, thus increasing the caller's social status, not unlike humans who look up to heroes. [GET SERIOUS!!! See any squirrels with Purple Hearts lately?]
Hare said other animals, such as birds, probably understand at least some squirrel language, since they also may benefit from the alarm calls. [At least one Hare does...]
While chickadees and other birds often are welcomed into gardens by homeowners, squirrels frequently are viewed as pests. Hare wishes greater understanding of the complex social lives and communication systems of squirrels will provide "hope that humans will gain a greater appreciation and stop persecuting these animals." [Not 'complex' at all. Eat the birds' food, die!]