I’m a squirrel behavior scientist, and the question I often ask is, “How do I get them out of my yard?” »
A squirrel’s life is not as easy as you might think. These animals are relatively solitary and must protect their hard-earned food supplies to survive the harsh Canadian winters. What interests me and my students most is how squirrels use sound, or what we call vocal communication, to survive in a harsh reality.
The North American red squirrel lives a somewhat solitary life. It spends most of its days in an area of 50-100 square meters, foraging for pinecones and other foods such as berries and mushrooms.
Squirrels collect pinecones all summer and fall, and store them in a place called a lair. They must work to protect their lair, because they are animals that steal a lot from each other. In fact, a squirrel can steal up to 90% of its reserves from neighboring individuals.
These little monsters go back and forth pregnant and stealing the pine cones that will allow them to survive the harsh Canadian winter. As they move, they often make a loud shriek, called a rattle call, which I pay attention to. My students and I observe and record squirrels to understand the role of these calls.
In the past, this call was supposed to be used to warn other squirrels about entering an area – meaning, in a way: If you do enter, you risk being attacked by the individual who lives there. My research has led to a slightly different view of these tears.
Neighbors and strangers
It is possible that the call does indeed warn other squirrels to stay away, but its primary function is to identify its origin to those who hear it. When a squirrel moves on its territory or on the territory of its neighbors, it makes intermittently crackling sounds. These calls announce who he is and where he is. Thus, squirrels know the position of their neighbors all day long. This information can help reduce aggressive interactions, chases, and fights.
This call can also indicate which neighbors are likely to steal from and who are a threat. Some individuals are at greater risk of theft than others.
In behavioral ecology, this phenomenon is called the “dear enemy” effect. This means that in order to hold a territory, it is useful to know the relative threat posed by neighbors as compared to the threat posed by outsiders. In general, the neighbor that the animal knows is less dangerous than a stranger.
In the case of the red squirrel, it has been shown that not all neighbors present the same degree of threat. Therefore, getting to know your neighbor by his yell allows you to know the dangers you are in and respond in the right way.
Self-declaration or recognition is a common vocal behavior for many animals. Many species of marine mammals, such as dolphins and seals, make calls containing information about the individual making them. They make it possible to get acquainted with social companions and offspring.
Many primate species also provide information about their identity through their calls. Again, this is often used in social interactions to reduce aggression while foraging. This is the case among other things with baboons and capuchins. It is therefore not surprising that an animal such as a red squirrel also uses information about a neighbor’s identity to manage complex interactions related to a region.
My students and I have found that squirrels make these calls throughout their territory as well as those of their close neighbors. By observing when and where squirrels give their roaring call, we hope to be able to demonstrate that this signal serves to announce who they are and where they are, and not just to chase others away from their territory.