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Have you ever seen a prairie vole? If you traverse the grasslands of Canada or the U.S., you might have caught a glimpse of the little, brown, furry rodent. And like mice and rats which are often used in scientific studies to mimic the behaviors of humans, these nocturnal, herbivorous prairie voles are more like us than you might think.

“Prairie voles raise their pups together, i.e., they are biparental,” Oliver J. Bosch told us. Bosch is one of the authors of a new study on the emotional health of single prairie vole mothers. Less than 10 per cent of mammals engage in biparental care.

“This makes the prairie vole an ideal animal model to study the underlying mechanisms of forming a pair bond but, more interesting to me, also losing a partner.”

Though previous studies have shown increased anxiety and depressive-like behavior when male prairie voles were separated from their female partners, Bosch and his colleagues wanted to examine what would happen to the stress level of a lactating mother prairie vole who lost her partner and had to raise her offspring by herself and the implications for human single mothers.

According to the 2017 U.S. Census Bureau, over 17 million children or 1 in 4 children are being raised without a father. Of 11,667 million single parent families in the U.S., 81.4 per cent are being headed by single mothers. Of those, 35.6 per cent were considered poor, 27.5 per cent did not have a job, and 31.6 per cent were food insecure.

According to Statistics Canada, lone-parent families increased from 289,000 in 1976 to 698,000 in 2014 and are four times more likely to live in poverty than in families with two parents.

The financial burden faced by many single mothers has been found to be the main reason single mothers are more likely to experience mental health problems than mothers with partners. In an Australian study of 354 single mothers and 1689 partnered mothers, 28.7 per cent of single mothers were found to have a mental disability compared with 15.7 per cent of partnered mothers.

Bosch’s study published in the Journal of Behavioural Brain Research shows that although the level of maternal care of single prairie vole mothers is on par with partnered mothers, the emotional health of single mothers is much more negatively affected than in female prairie voles in a dual parental arrangement.

The study, titled, Abandoned prairie vole mothers show normal maternal care but altered emotionality: Potential influence of the brain corticotropin-releasing factor system, was authored by Bosch, Tobias T. Pohl, Inga D. Newmann, and Larry J. Young of the Department of Behavioural and Molecular Neurobiology at the university of Regensburg in Germany and the Center for Translational Social Neuroscience at Emory University in Atlanta, Georgia.

Despite a previous study that showed that the level of maternal care remained consistent despite the absence of a partner, the authors of this study wanted to see whether the single prairie vole mother’s emotions would be affected if her partner was not present. Researchers carried out the study by removing the male partner from his pregnant female prairie vole partner’s nest a few days before the expected day of delivery and then monitored maternal care postpartum.

“The results were striking,” Bosch told us. “We found that a single mom shows unaltered maternal behavior compared to a biparental mom, but when tested for emotionality, single moms were highly anxious and showed highly increased depressive-like behavior. These parameters were even stronger than what we saw in the separated males from our previous studies see above. Hence, single moms try to provide their offspring with the same amount of care despite her emotionality which really suffers from the situation.”

Researchers then tested whether a control substance or effective blocker of the stress system could help the single prairie vole mothers and found that the moms with a blocked stress system showed absolutely normal emotionality.

“Fantastic, it worked,” Bosch told us. “We can rescue the emotionality of depressed single moms.”

Bosch and his team of researchers are hoping their study can shed light on the future treatment of depressed single moms as well as for postpartum mood disorders.