Why are humans the only species to cry “emotional” tears?

Humans are the only species that sheds emotional tears: from Darwin to the latest research, we explore the mystery and meaning of tears that arise from the deepest feelings

Charles Darwinin his famous scientific approach, dismissed the emotional tears as an “unnecessarily curious” phenomenon. But today, this very intimate and human act turns out to be anything but meaningless. Crying is not just a biological reflex: it is an experience that defines us, a universal language that speaks directly to the heart.

We human beings shed tears for a thousand reasons: for pain, joy, nostalgia, and even when a song or a scene from a film brings back distant memories. But why are we the only ones, among millions of living species, to do this? And why can our crying arise from such a complex mixture of feelings? Science is still trying to answer, but in the meantime, we can explore some of the fascinating truths already discovered.

Tears: three types, three functions

Not all tears are the same. Indeed, there are three main types, each with a very specific purpose:

1. Basal tears: Invisible and constant, these tears keep the eyes hydrated and protected. A small biological miracle, necessary for our daily well-being.
2. Reflex tears: They are the ones that flow when we slice an onion or when a speck of dust irritates us. Their task is clear: to free the eyes from any external agent.
3. Emotional tears: Something unique comes into play here. When we cry for an emotion, our tears do not have an immediate physical cause, but are activated by deep areas of the brain linked to more complex feelings.

The ancients tried to explain this phenomenon with poetic ideas. For Old Testament Jews, tears were symbolic of a broken heart; the Greeks, however, believed that it was the mind that generated them. Then, in 1662, Danish scientist Niels Stensen discovered the lacrimal gland, confirming that tears had a physical origin. But despite this revelation, the meaning of emotional tears remained shrouded in mystery.

And here we come to Darwin, who branded emotional tears as “purposeless.” But was he right? Today we know that, although they are mainly composed of water, mucus and antibacterial proteins, these tears have something special: they are not a simple physical response, but the result of a complex interaction between mind and body.

Crying: a gift that evolves with age

Human crying begins early, but not in the way we might imagine. Newborns, for example, cry without tears: these appear only after a few weeks, when the lacrimal glands mature. That initial cry, however, has a crucial purpose: to get the parents’ attention.

But then, why do adults cry visible emotional tears? One theory suggests that emotional crying may be an evolution of communication: tears convey suffering silently, without attracting unwanted attention, as would happen with a cry. In essence, it is a nonverbal language that strengthens social bonds and communicates empathy.

Over time, our relationship with crying changes. As children, we cry mostly from physical pain. But as adults, crying becomes a way to express what words cannot say: sadness, nostalgia, happiness, anger. In this sense, crying becomes a social glue, capable of uniting people in moments of sharing.

Crying: a taboo for men?

We don’t all cry the same way. The frequency of tears, for example, varies enormously between men and women. Studies show that women, on average, cry two to three times more than men. Why? A combination of biological and cultural factors.

On the one hand, hormones play a crucial role: testosterone seems to inhibit crying, while prolactin, higher in women, could promote it. On the other hand, there are social norms, which often teach kids “not to cry” and to show themselves strong.

But there’s more: our character and context play an important role. People who are empathetic or more prone to emotional sensitivity tend to cry more. Tiredness or one too many drinks can also make tears easier.

Because crying is good for you

There’s a reason why we feel better after a good cry. Crying, in fact, is not only an emotional outlet, but also a therapeutic act. It releases chemicals that help calm the body and often strengthens bonds with those around us.

Receiving a hug or a kind word during a moment of crying amplifies its positive effects, transforming this experience into an opportunity for deep connection.

And so, while Darwin saw emotional tears as an evolutionary mistake, today we know that Crying is an essential part of what it means to be human.