Motherhood, as we know it today, has evolved over millions of years and shaped life on this planet in more ways than we can count. As we learn more about motherhood in the animal kingdom, we find ourselves in solemn wonder at this awe-inspiring gift of nature.
Here we share three science facts about motherhood that have provided us with a new perspective on how amazing moms are. Let’s get right to it.
All Emotions Evolved From Motherhood
Morganucodon is considered to be one of the first mammalian species. It’s the common ancestor of all mammals today, including humans. It was also the first of our ancestors to start giving live birth instead of laying eggs. Scientists believe that keeping the eggs inside as the young developed provided protection against egg-eating predators—which at the time of Morganucodon, were Jurassic animals including dinosaurs.
Giving live birth made it easier for moms to recognize their own babies once they were born. This gave them the opportunity to provide for and take care of their children to ensure their survival—and love was born.
The first mammals were also the first animals to develop the limbic system, which I also called the “mammalian brain”. The limbic system is responsible for all emotions and experiences, including happiness, sadness, excitement, disgust, anger, satisfaction, and love.
These emotions—love in particular—drove the first mammalian mothers to take care of their young and later evolved to allow bonding, social structures, and relationships. Without the first moms, we would all have a lizard brain—with instincts for survival and reproduction and nothing else.
Non-Mammalian Moms Also Love Their Children, but We Will Never Know How It Feels
Mammals are the only animals with the limbic system, the part of the brain responsible for all the emotions we feel. This would imply that mammal moms are the only moms who love their children, but that’s not true.
Many birds care for their young for a long period after the eggs are hatched. Parental care is also observed in some fish, reptiles, amphibians, and insects such as ants and bees. None of these species have a limbic system, so we know that can’t experience love and affection. What’s going on here?
This is a case of what’s called “convergent evolution”. Similar traits and organs can evolve multiple times in different species independently from each other.
For instance, birds, bats, and insects have wings that serve the same purpose: flying. However, these wings are anatomically different and evolved independently from each other at different times in the history of life. Whales and dolphins are mammals that used to walk on land, but their limbs have evolved into fins and their bodies into shapes similar to sharks for better swimming.
Non-mammal moms that care for their younglings are thought to evolved new brain parts independently from mammals that make them feel something similar to love. However, what they feel for their children is entirely different from what humans and other mammals feel. We can’t even use the word “feel” for it because feelings are unique to our experiences enabled by the limbic system.
We can never comprehend the “love” birds feel for their kids—we don’t even have the part of the brain responsible for it. All we can do is stand in awe of the universality of motherhood.
Moms Love Their Children More Than Dads, According to Science
This is something many of us know from experience while others argue against it. Although there are exceptions to this rule, the science is clear.
Moms typically invest more resources in bringing new life into the world than dads do. Eggs are larger than sperm and take more resources to make. Childbearing also takes more time and resources than conception. Moms have more to lose than dads if an offspring fails to reach maturity, which is why moms throughout the animal kingdom have evolved stronger feelings of love than dads.
In many mammals and birds, moms are the only parent who takes care of and raises the children after birth. Even in monogamous species where both parents participate in raising the children, moms tend to be more invested.
Humans are more complex than other animals and our values and social norms determine our behavior as much as our emotions and instincts. Still, on a subconscious level, our moms may love us more than our dads.