Wild North American red squirrels are a solitary and territorial species, and defend their territories year-round through vocalizations called “rattles.” Since competition to survive is the typical rule in nature, researchers are often interested in whether and how social relationships within species can promote survival. While most research on this topic has focused on animals that live in groups, researchers at the University of Guelph in Yukon, Canada decided instead to look at how these solitary red squirrels interact with their neighbors.
The researchers followed a population of 1,009 squirrels over the course of 22 years using colored tags attached to the animals’ ears. They found that only a small percentage of squirrels maintained their neighbors from one year to the next, but the squirrels that did so showed significant differences. Squirrels that lived next to each other year after year spent less time defending their own territories, and were less likely to intrude on neighboring territories and steal each other’s food. As a result, these squirrels had increased survival rates and produced more offspring. These benefits were especially pronounced in older squirrels, where the negative effects of aging could be greatly offset by the benefits from maintaining their neighbors. The survival rates of five-year-old squirrels who didn’t maintain neighbors decreased to 59% from 68% in the previous year, but actually increased to 74% among those that did keep social relationships with their neighbors.
This is the first study where reduced aggression towards familiar neighbors has been tied to a survival advantage. Even though red squirrels do not like their neighbors and are in constant competition for food, mates, and resources, these results show that getting along can help them survive. While it is unknown what exactly which cooperative behaviors bring about this benefit, this study helps us better understand the evolution of territorial and migratory systems, and points to an interesting lesson about the value of social relationships.
Professor Andrew McAdam is an adjunct faculty at the University of Guelph in Ontario, Canada. Dr. Erin Siracusa is a postdoctoral researcher at the University of Exeter, who conducted this research with her colleagues as a doctoral candidate at the University of Guelph.
Managing Correspondent: Lauren Davancaze
Press Articles: “Territorial red squirrels live longer when they’re friendly with their neighbors,” Science Daily
Original Journal Article: “Familiar Neighbors, but Not Relatives, Enhance Fitness in a Territorial Mammal,” Current Biology
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