Voles are small rodents often mistaken for mice, but their social lives are distinctly different. Whether a vole mates for life depends on its species. Some voles form lifelong partnerships, while others are more solitary and promiscuous.
The Monogamous Prairie Vole
The prairie vole is an example of monogamy in the animal kingdom, forming lasting social pair-bonds. The male and female share a nest, groom each other, and jointly raise their pups. This partnership endures for their entire lives, and if one partner dies, the survivor usually does not seek a new mate.
This bond extends to defending their territory and partner from intruders. After mating, both male and female prairie voles become aggressive toward unfamiliar voles of their own sex. While socially monogamous, they are not always sexually faithful, occasionally mating with others. The primary social structure, however, remains the dedicated pair-bond.
The Promiscuous Meadow Vole
In contrast to their prairie relatives, meadow voles are non-monogamous. They do not form lasting pair-bonds, and individuals of both sexes mate with multiple partners. After mating, there is little to no continued social interaction between the male and female.
This system means male meadow voles play no part in nesting or raising the young. Unlike the cooperative family units of prairie voles, meadow vole mothers raise their litters alone.
Hormones and Vole Relationships
The different social behaviors are linked to brain chemistry, specifically the hormones oxytocin and vasopressin. These neurochemicals are involved in social recognition and bonding. The difference between the species is not the amount of hormones they produce, but the density and distribution of their receptors in the brain.
In monogamous prairie voles, receptors for vasopressin (in males) and oxytocin (in females) are concentrated in the brain’s reward system. This means social behaviors like huddling with a partner trigger a rewarding sensation, reinforcing the bond. The brain structure of prairie voles makes pair-bonding feel good, encouraging a lasting connection.
In meadow voles, these hormone receptors are in brain areas not linked to reward pathways, so mating does not produce the same reinforcing effect. Researchers have shown that by increasing vasopressin receptors in the reward centers of promiscuous voles, they can be induced to form pair-bonds. This demonstrates the direct link between receptor locations and mating behavior.