Humans are obsessed with finding "the one" that could become their lifetime companion. But they are not the only ones as some animals, like lemurs, also practice monogamy.

Lemurs, such as the red-bellied lemurs and mongoose lemurs that are among the animals who stay with a single partner for all their lives to raise their young and defend their territory.

The new study, published in Scientific Reports, examines the monogamous relationship between the lemurs, the distant primate cousins of humans. Once they become bonded with another lemur. they spend much of their time grooming each other or huddled side by side with their tails wrapped around each other's bodies.

Monogamy is Rare

Biologists said that monogamy is somewhat a mystery because it cannot always be observed in many species in the animal kingdom.

Although 90% of birds stay with the same partner throughout their lifetime, only about 3% to 5% of mammals do. That means species of over 6,5000 known species of mammals engage in open relationships, having not just one partner but multiple.

Postdoctoral associate Nicholas Grebe who works in Professor Christine Drea's lab at Duke University, the lead author of the study, said that monogamy is just an uncommon arrangement.

This raises the question of what makes some species to be biologically monogamous while others are not.

ALSO READ: What is the Socioemotional Selectivity Theory?


Cuddle Chemicals: Oxytocin and Vasopressin

Science Focus reported that the team from Duke University found that it seems the brain circuitry may hold the key to making love last in some species and not in others. 

In the last 30 years, scientists have been studying rodents and found that there are two hormones that are released when mating. These so-called cuddle hormones are oxytocin and vasopressin that play a significant role in establishing long-term relationships.

For instance, when researchers compared the brains of monogamous prairie coles with montane voles and meadow voles who do not practice monogamy, they found that prairie voles had more docking sites for the cuddle hormones that are mostly found in the reward system of the brain.

Meanwhile, in the new study, brain images of the lemurs revealed that oxytocin and vasopressin appear to act on different parts of their brains compared to previous studies on rodents. This means that monogamy in animals could be more complex than once thought.

"There are probably a number of different ways through which monogamy is instantiated within the brain, and it depends on what animals we're looking at," said Dr. Nicholas Grebe, the lead author of the study. "There's more going on than we originally thought."

What Can Lemurs Teach Humans About Love?

The authors said that the findings caution humans to draw simple conclusions about human social behaviors based on rodent experiments, Futurity reported.

Cuddle hormone oxytocin may be the "potion for devotion" but the combined actions and interactions of multiple brain chemicals and ecological factors could also be a factor for long-lasting bonds in lemurs, primates, and humans.

Grebe noted that there could be several different ways through which monogamy is established within the brain, depending on what type of animals are being studied. 

RELATED TOPIC: Grandmothers Are The Key To Romantic, Monogamous Relationships -- Study

Check out more news and information on Relationship on Science Times.