It turns out they have a number of vocal and tail signals that have different meanings depending on how they are used. Thaddeus McRae and Steven Green of the University of Miami looked at whether these different alarm signals were used by squirrels , either individually or in combination, in response to different kinds of threats.
Gray squirrels have three different vocal alarms, which they produce when they spot a potential predator nearby. The kuk heard in the example above is short, sharp, broad-frequency sound. The quaa is essentially a longer version of the kuk, but it can be varying lengths. Both kuks and quaas can be heard in the example below. In addition to these vocal alarms, squirrels have two types of tail signals. A twitch looks like a wave running through the tail. It's a controlled movement in which the path of the tail tip usually forms a simple arc.
A flag is a more conspicuous whipping motion. During a flag see video below , the squirrel's tail tip can move in arcs, figure eights, circles, and various squiggles. View Iframe URL. McRae and Green tested whether these different vocal and visual alarms were associated with particular types of predators. They studied a wild population of gray squirrels on the University of Miami campus.
These squirrels have two main types of predators: aerial predators, such as hawks, and terrestrial predators, particularly domestic cats. The researchers exposed the squirrels to five kinds of potentially threatening stimuli. They simulated a hawk approach by throwing a styrofoam glider painted to look like a hawk in the air. They simulated a cat attack with a remote-controlled model cat on wheels, driven toward the squirrel.
To see if the manner of approach terrestrial versus aerial or physical resemblance to a predator affected the squirrels' alarms, the researchers also presented the squirrels with an object that didn't resemble any predators at all — a red ball — and either rolled it towards the squirrels or threw it overhead like the model hawk.
Overall, McRae and Green found the squirrels have an alarm system with different degrees of specificity. Some, but not all, of the alarm signals were associated with predator type, and combinations of tail signals and vocalizations were more strongly associated with threats than either type of signal alone.
In some cases, the squirrel is telling a predator that it sees it, is well aware that it is being stalked, and so there will be no element of surprise.
At other times, the squirrel sends out an alarm, telling other squirrels that something bad is going on. Squirrels have other conversations, too. The signals can vary among the different species of squirrels. DEAR JOAN: We had the problem a lot of your readers have been writing in about, with the raccoons peeling back our backyard turf like the lid of a sardine can.
The solution we found was inexpensive and easy: bird netting. If you see one chattering inside your house, it will probably retreat further inward. A squirrel may moan and flick its tail in your direction, or it may just flick its tail, to indicate that it may think you are a threat. This can be a problem, of course, if you find one living in your house!
Other common specimens such as the Eastern Gray Squirrel make a wide variety of noises like buzzes and moans in addition to chattering and barking. Do not attempt to catch or trap the squirrel yourself.
Make sure your kids are aware of this, too: A squirrel can give you a nasty bite if it feels threatened. If you hear a squirrel barking, the best course of action is to simply leave it alone.
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