Last updated: 28th September 2023
Humans are one of a few mammals that stay together through long periods, with many staying together their whole adult lives. While this is rare in the animal world, there are some that are monogamous.
Only 3-5% of all species of mammals are monogamous. These include the gray wolf, red and gray fox, beavers, sea otters, prairie voles, and the California deer mouse.
There are different types of monogamy that some mammals practice. Please read on if you want to know more.
What Is Monogamy?
Monogamy is defined as having only one mate. In mammals, monogamy is the mating couple remaining together through several breeding seasons. This may not be a lifetime relationship, but it does cover a large portion of their lifespan. If one of the pair dies, the remaining one may mate with a new individual.
For mammals that do not have long-term relationships, monogamy can be defined as mating for the breeding season, with the male staying with the female after mating and during the rearing of offspring.
Although some mammals are monogamous, it has been estimated that only about 3-5% of mammals practice monogamy.
Many mammals invest considerable time and energy in raising their young. Many males will not raise offspring from another male, so they will stay faithful to their partners, ensuring that their chosen female will birth only his offspring.
There are instances where the male guards the female to make sure no other individual breaks this bond. This protection ensures that the female does not mate with any other individuals, and although this may not qualify as monogamy it does explain why some species stay together for at least as long as the gestation period.
There are two types of monogamy in the animal world
- Social Monogamy Social monogamy does not guarantee sexual faithfulness between male and female partners. In most cases, the two individuals will stay together but will mate with others. However, conflicts may arise as a result of infidelity.
- Genetic Monogamy Genetic monogamy is the opposite of a social monogamous relationship. In a genetically monogamous relationship, the male and female stay faithful to each other. Once they find their partner, they will stay together, mating for life.
In a wolf pack, there is a clear hierarchy led by an alpha male and his female partner. It is within this dominant pair that breeding occurs, and they are responsible for producing offspring that expand the pack. The alpha male plays a pivotal role in the group, determining the extent of their hunting grounds and leading the pack to new locations. Each year, the dominant pair gives birth to a litter of pups, contributing to the growth of the pack.
When encountering a lone wolf in the wild, it is often indicative of a wolf searching for a partner to establish a new pack. This solitary behavior highlights the importance of companionship and cooperative hunting for these highly social animals.
California Deer mouse
The California deer mouse (Peromyscus californicus) native to California and Mexico, displays unique social and mating behaviors. Upon reaching sexual maturity, they form lifelong pairs, staying together and mating exclusively with their chosen partner.
Both male and female California deer mice exhibit territorial tendencies and collaborate to protect their nest. The males, in particular, can be quite aggressive towards other males, a behavior aimed at intimidating potential competitors for the attention of their mate and asserting dominance.
California deer mice exclusively mate with their bonded partners and do not reproduce with unfamiliar individuals. Once the female becomes pregnant, she gives birth to a litter of pups, typically consisting of two offspring. Remarkably, the bonded pair can produce multiple litters in a single year, sometimes as many as six.
The male takes an active role in nurturing the young, sharing parenting duties equally with the female. This cooperative effort ensures the well-being and survival of their offspring.
Prairie voles (Microtus ochrogaster) are genetically predisposed to form long-term mating partnerships. When they find their mates, both males and females establish a deep bond. Males typically initiate courtship, and once the female enters the estrus phase, they mate.
Hormones like oxytocin and vasopressin play a crucial role in fostering bonding among prairie voles. Vasopressin is released when a prairie vole finds a partner and mates, activating specific brain receptors associated with pleasure and reward. Oxytocin, another hormone, facilitates social bonds, maternal bonding, and the birthing process.
Prairie voles exhibit a higher density of receptors for vasopressin and oxytocin hormones compared to non-monogamous species. When a pair of prairie voles mates, their brains become wired to associate pleasure and the rewarding aspects of mating exclusively with each other. This phenomenon explains why prairie voles form such strong and lifelong bonds.
Male prairie voles remain involved throughout the pregnancy and actively participate in parenting once the offspring are born, further solidifying the strength of their monogamous relationships.
Beavers (Castor canadensis) are another example of mammals that exhibit monogamous behavior, forming lifelong partnerships with a single mate. When they’re not busy with their remarkable landscape restructuring and engineering activities, beavers actively seek out their long-term companions.
Beavers typically reside in colonies created by a monogamous male and female pair. The offspring produced by this couple contributes to the growth of the colony. A typical beaver settlement comprises a monogamous couple, their young offspring, and older kits born in the preceding year.
As young beaver kits reach the age of two, they become ready to leave the colony. At this stage, they embark on a quest to find their own monogamous mate, continuing the cycle of lifelong partnerships.
While beavers form monogamous bonds, they are not entirely faithful to their mates. Occasionally, they may engage in mating with individuals other than their primary partner. In the event of a partner’s death, a surviving beaver will actively seek a new mate, underscoring their capacity for forming enduring relationships.
Sea otters (Enhydra lutris) are often regarded as one of the most romantic mammals due to their charming behavior of holding hands. This gesture, facilitated by their dexterous front paws, serves not only as a practical means to stay connected but also as a symbol of their strong social bonds.
Beyond their endearing hand-holding, sea otters are highly social animals that form enduring partnerships. They choose one mate and remain faithful for life, creating a family group that includes their offspring.
These devoted pairs engage in various activities together, whether it’s traveling, playing, or hunting. Unlike many monogamous mammals that cohabitate, sea otters maintain separate male and female territories while still enjoying a profound, lifelong connection.
Sea otters go through a yearly mating ritual. The male initiates courtship by approaching the female and displaying interest. The female responds by engaging in playful and affectionate interactions with her partner, often rolling around together. In some cases, the male may gently bite the female’s nose as a way to express his courtship intentions.
The gray fox (Urocyon cinereoargenteus) is a monogamous species, forming a lifelong partnership with a single mate. These monogamous pairs engage in breeding once a year during the designated breeding season.
However, what sets gray foxes apart from some other species is their unique social behavior. Outside of the breeding season and the period of raising newborn kits, adult gray foxes are solitary creatures, preferring to live alone.
When a female gray fox gives birth, her partner takes an active role in parenting. The male assists in grooming the young kits and provides protection against potential predators. During this time, while the female is nursing, the male partner heads out to forage for food.
As the young foxes mature and become capable of leaving the den, the family group eventually disperses. This distinctive pattern of monogamy, cooperation in raising offspring, and solitary living during other times characterizes the social dynamics of gray foxes.
Coyotes (Canis latrans) stand out as a species that consistently forms and maintains exclusive mating partnerships. Even when the coyote population is high, they remain faithful to their chosen mates.
In these monogamous pairs, male coyotes actively participate in parenting the pups. Together, they establish and defend a territory, collaborating to build their den or locate a suitable birthing site for their offspring.
Coyotes display remarkable affection towards their mates. During the female’s pregnancy, the male takes on the role of the provider, embarking on hunting expeditions to bring back food for the family. After the pups are born, both parents take on the responsibilities of protecting and grooming their young, reinforcing their strong bond and commitment to raising their offspring together.
The red fox (Vulpes vulpes) is known to practice a form of social monogamy that is not a lifelong commitment, as seen in some other monogamous species. Instead, it revolves around the breeding season and the care of their offspring.
During the breeding season, which typically occurs in late winter, a special bond forms between male and female red foxes. This bond is essential for successful reproduction, as it ensures cooperation between the parents in raising their kits (young foxes). While this connection is not one of lifelong devotion, it is still critical for the survival of their offspring.
Outside of the breeding season, red foxes are not committed to their partners. Males and females may engage in mating with multiple partners, reflecting a more flexible approach to their social relationships. A male fox, known as a dog, may mate with several estrous (reproductively receptive) females, while a female fox, referred to as a vixen, might copulate with multiple males. This behavior allows for genetic diversity within the offspring.
However, once the breeding season arrives, both parents will reunite and stay in close proximity to each other. Their cooperation becomes essential during this time, as they work together to protect and raise their kits. The male actively participates in nurturing and guarding the young foxes, contributing to their survival and well-being.
References And Further Reading
- This book takes a comparative approach to monogamy across various species, including mammals, birds, and humans, offering a comprehensive examination of the topic.
- This research article provides valuable insights into the evolution of social monogamy in mammals, making it a useful reference for academic research.
Bryan Harding is a member of the American Society of Mammalogists and a member of the American Birding Association. Bryan is especially fond of mammals and has studied and worked with them around the world. Bryan serves as owner, writer, and publisher of North American Nature.