Though red squirrels are a solitary and territorial species, the results of a 22-year study of these squirrels suggests that they have a higher chance of survival and a greater number of offspring when living near the same neighbors year after year. These benefits were even more pronounced in older squirrels, whom the data suggested could sharply offset the effects of aging by maintaining all of their neighbors from one year to the next.
Researchers set out to discover whether there were any survival and reproduction benefits for squirrels who lived near their blood relatives or lived near non-related squirrels over a number of years. What they found was that living near relatives didn’t provide any biological benefits — which was surprising, since animals that share the same genes are generally more likely to act altruistically toward one another. But they did find that regardless of relatedness, the longer squirrels lived with each other, the more likely they were to survive into the next year and produce more offspring.
The benefits of this familiarity among older squirrels were even more pronounced. According to the lead researcher, Dr. Erin Siracusa, “The benefits of familiarity were strong enough to completely offset the negative effects of aging”.
Journal Reference: Erin R. Siracusa, Stan Boutin, Ben Dantzer, Jeffrey E. Lane, David W. Coltman, Andrew G. Mcadam. Familiar Neighbors, but Not Relatives, Enhance Fitness in a Territorial Mammal. Current Biology, 2020 DOI: 10.1016/j.cub.2020.10.072