Smiling Mammals

By: Paul S Cilwa	Posted: 1/11/2024	Page Views: 521
Hashtags: #Autobiography
Smile, and the whole world smiles with you.
Estimated reading time: 4 minute(s) (786 words)

If you see someone without a smile, give him yours! This quote from the beloved (and always smiling) Dolly Parton points out the fact that smiles are contagious. When we see one, our gut reflex is to smile back—even if the smile is in a photograph, such as the one above. But why is that?

Biologically speaking, smiles are contagious due to a combination of neurological and psychological processes. When we see someone smiling, our brain's mirror neurons activate, which are responsible for mimicking the actions of others. This mirroring effect allows us to empathize and understand the emotions of the person smiling. As a result, we often unconsciously replicate their smile, which in turn can trigger the release of neurotransmitters like dopamine and endorphins in our own brain, making us feel happier.

Additionally, the orbitofrontal cortex, a region of the brain associated with sensory rewards, is activated when we see someone smiling. This activation gives us a sense of reward, which feels good and often leads to us smiling in response. This contagious nature of smiling is a social tool that helps build connections and communicate positive emotions, reinforcing social bonds and cooperative behaviors within groups.

But here's the thing: All mammals smile, and seem to do so for the same reasons we do: in reaction to feelings of happiness, joy and/or contentment. Smiling is a universal expression that involves specific muscles in the face being activated, particularly the zygomaticus major and minor, which pull the corners of the mouth upwards. And all mammals share the same muscles in the same configuration and wired in the same way to the same parts of the brains. And it's a feedback loop: The muscles are activated when the brain feels happy; and when the muscles are activated, they make the brain feel happy. That's the science behind the truism that smiling intentionally when sad can lift one's mood.

Upon receiving these signals, the brain responds by releasing endorphins from the pituitary gland and the hypothalamus into the bloodstream. Endorphins are opioid peptides that act as neurotransmitters, often referred to as the body's natural painkillers. They are released during various emotional states, including stress, exercise, excitement, pain, love, and of course, when smiling. The release of endorphins leads to a feeling of well-being and happiness

The concept of universal in the context of smiling among mammals suggests that this behavior has deep evolutionary roots, likely tracing back to the earliest mammals. The fact that many mammals exhibit some form of a smile-like expression, not just us primates, indicates that the behavior evolved as a means of communication and social interaction early in mammalian history.

In primates, for example, baring teeth is not always an aggressive gesture but can be a sign of submission or non-aggression, which is believed to be a precursor to the human smile. This behavior is instinctual and does not require learning, as even blind individuals display smiles in appropriate social contexts, demonstrating that it is a preprogrammed behavior.

The evolution of smiling in mammals is complex, but it is clear that the behavior has been conserved and adapted for various purposes throughout mammalian evolution. Smiling, as we understand it in humans, may have evolved from these earlier forms of tooth-baring as a way to express non-aggression and to foster social bonds. This adaptation would have been advantageous for early mammals, promoting group cohesion and communication, which are essential for survival.

Furthermore, the similarity between smiling and other facial expressions related to defensive reflexes, such as laughter and crying, suggests that these expressions may have originated from common protective behaviors. Over time, these expressions could have been co-opted for social signaling, further supporting the idea that smiling has a long-standing evolutionary history among mammals.

And please let's not get into the falsehood that, It's not really a smile; it's just the way their mouths are shaped. In response I present two dolphins, one of whom is not smiling.

In summary, the universality of smile-like expressions among mammals points to an evolutionary origin that predates the diversification of modern mammal species. This shared trait among mammals underscores the importance of facial expressions as a fundamental aspect of social behavior and communication in the animal kingdom.

So, check out the additional examples I've culled from the Internet (plus a picture of my own dog, Ella). Try not to smile when you see them! You can't!