Prairie voles with offspring
Photo: Todd Ahern / Emory University
It is an unusual life plan for rodents: the prairie vole lives in a loyal partnership and takes devoted care of its offspring.
Pairs of mice often raise offspring from other pairs as if they were their own, according to a news article on the Nature magazine website.
So far, many scientists have assumed that the bonding hormone oxytocin is crucial for the animals' strong bond.
However, a study published in the journal Neuron challenges this assumption.
Binding even without an oxytocin receptor
Using the Crispr gene scissors, the experts modified the genome of prairie voles in such a way that their bodies could no longer recognize oxytocin because they lacked the receptor for it.
“Unexpectedly” it turned out that the animals were nevertheless responsible parents and entered into monogamous relationships.
Researchers have long been fascinated by the small rodents.
"There is an uncanny similarity between the social behavior of voles and humans," says Nirao Shah, a neuroscientist at Stanford University in California in Nature.
"Prairie voles are one of the few mammal species that exhibit social bonding."
A central role in social behavior is attributed to the hormone oxytocin.
In humans, oxytocin levels rise in response to social interactions.
The hormone is also important in stimulating uterine contractions during childbirth, subsequent milk production, and the bond between parent and child.
According to the study, mother voles that lacked the oxytocin receptor were still able to suckle their offspring – even though their milk supply was reduced.
Drug blockade reverses monogamy
The experts were particularly surprised by the result because previous experiments had pointed in a different direction.
If drugs blocked the oxytocin receptor in the brain of the vole, so that the hormone could no longer work there, monogamy and the typical pair-bonding behavior were reversed.
It is still unclear why the drug blockade influences the social behavior of the animals, but not the general absence of the receptor.
Experts speculate that voles, which are born lacking the binding site for the binding hormone, evolve an alternative mechanism that enables them to engage in long-term social relationships.
In contrast, animals whose receptors are suddenly switched off may not be able to spontaneously compensate for the absence.