CAMBRIDGE, England — At our very core, we are social beings. Dating back thousands of years people have always gathered together to form communities, friendships, and families. Social behavior is quite literally in our DNA, and while everyone can appreciate the occasional quiet night in, maintaining an active social life has long been associated with improved well being in humans. Now, a new study finds that the same holds true for crows.
Researchers from Anglia Ruskin University studied a group of captive crows for over six years, and found that the more sociable crows with more “friends” were healthier than crows with fewer social interactions. Each crow’s behavior was monitored as they interacted with different sized groups of other crows, and friendships between crows were even measured using a ranking system. Simultaneously, the birds’ droppings were analyzed to look for coccidian oocyst, a common gastrointestinal parasite among crows that can be detrimental to their health.
On a physiological level, the more sociable crows should have been at a greater risk of contracting parasites and disease by constantly being around other birds. However, the researchers actually found the exact opposite. The friendlier crows with stronger social bonds, larger families, and larger living groups in general, excreted significantly smaller levels of parasites in their droppings in comparison to more anti-social ones.
The research team also looked to see if a crow’s dominance within its group played a role in their health, but they found no such relationship. But, they did note that males were a bit more likely (33%) to carry a parasite than females (28%).
“It is a commonly-held belief that animals in larger groups are less healthy, as illness spreads from individual to individual more easily. We also know from previous studies that aggressive social interactions can be stressful for birds and that over time chronic activation of the physiological stress response can dampen the immune system, which can make individuals more susceptible to parasites,” explains research leader Dr. Claudia Wascher in a release.
“Therefore the results from our six-year study, showing a correlation between sociability and health, are significant. It could be that having close social bonds reduces stress levels in crows, which in turn makes them less susceptible to parasites,” Dr. Wascher concludes. “It could also be that healthier crows are more sociable. However, as many of the birds we studied were socializing within captive family groups, dictated by the number of crows within that family, we believe that social bonds in general affect the health of crows, and not vice versa.”
The study is published in the scientific journal Animal Behaviour.