Humans, like many animals before them, are very social creatures. But depending on each individual, we either feel comfortable or uncomfortable in crowds. This isn’t the same for all mammals however, as a new study from Duke University involving a small rodent that mates for life suggests that prairie voles like crowds and dislike being alone.
The study involving the small mouse-like rodents was published in the journal General and Comparative Endocrinology and was conducted by a team of researchers from the Duke University led by post-doctorate researcher Dimitri Blondel.
It was also part of a larger study targeting the way in which social stress caused by phenomena such as isolation and crowding affects the behavior and brain chemistry of many species, including humans.
Prairie voles are small social rodents familiar to the grasslands and meadows of the Midwest and to those of Canada.
Being one of the few mammals to mate for life, they have long been a subject of interest for scientists.
The team of researchers used an enclosed space in a hayfield in southern Illinois full of the little rodents and equipped with multiple gates and dividers that allowed them to separate and reunite the tiny social animals into larger and smaller spaces.
Special radio collars allowed the researchers to track the animals’ every movement. Fecal samples were also collected in order to measure the quantities of the stress hormone corticosterone present in the animals.
In one of the trials, 24 prairie voles were released in a quarter acre space, where they were able to roam free for three weeks at a density of 97 voles per acre. This was done twice – once in the summer and once in the fall.
Another test held at the same time saw 24 of the animals to roam around in a much larger area, at a density of 32 voles per acre.
With the study results in, the researchers were able to determine that despite the animals bumping into each other much more often in the tighter space, the same group showed the less amount of stress.
When the animal numbers tripled in the same enclosure, the prairie voles’ corticosterone levels dropped by 20%.
This has multiple explanations.
First of all, a thinner population meant slimmer chances of finding a mate. This also drove male prairie voles to mate with previously known females instead of going out to find new ones.
Lastly, a thinner population could also mean that predators are around, thus stressing out the tiny rodents.
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