It’s not unusual to hear stories from family members about loved ones who have passed away. One fascinating and surprising observation that often comes up is how a person behaves before their passing. Many people seem to get their affairs in order, such as saying goodbye, repairing strained relationships, and even giving away their cherished belongings. It feels like they sense something before anyone else does.
Some might shrug this off as coincidence, but others firmly believe that people know when their time is near.
Trying to understand the death of someone dear or imagining what happens in those final moments is a natural human curiosity. Scientists have found that when someone passes away, the body immediately begins to break down.
One chemical that emerges during this process is putrescine, which emits a foul and toxic odor. Researchers have discovered that humans subconsciously recognize this decomposing scent. What’s more, the smell triggers an immediate reaction.
Animals Can Smell Death Too, And They React Accordingly
Just like animals sense danger from predators or other threats, humans also sense the threat of death through smell.
A study led by Arnaud Wisman from the University of Kent’s School of Psychology in Canterbury, UK, and Ilan Shira from the Department of Behavioral Sciences at Arkansas Tech University in Russellville, AK, indicated that animals and humans are not so different after all.
The ability to detect chemical scents is vital for survival across species. For humans, the threat of death is conveyed through smell.
Putrescine: The Dangerous Scent Released During Decomposition
Putrescine, released when a body decays, acts as both a sign of decomposition and a warning signal. People respond to this scent on both conscious and subconscious levels.
In one experiment, people at a site with putrescine immediately moved away from the odor. This aligns with the fight-or-flight response we all have.
When animals sense danger, their two primary options are to fight the threat or flee from it. Interestingly, humans show a similar reaction.
Other Scents That Send Signals
Humans also respond to other scents like sweat. Studies have shown that sweat collected from individuals in fearful situations can trigger an automatic startled reaction in others.
“We don’t always understand why we like or dislike certain smells, nor are we usually aware of how these scents affect our emotions, preferences, and attitudes,” explain Wisman and Shira.
“It’s challenging to think of a scent as frightening,” add the researchers. These scents make us more aware and alert of our environments.
Humans Prefer to Avoid Danger Rather Than Confront It
Generally, people prefer to avoid confrontation—whether verbal or physical. Most choose to distance themselves from danger, only fighting when no other option remains.
The Dual Nature of Scent Responses: Survival vs. Attraction
Our responses to putrescine and s+ex pheromones differ, but both are based on scent. S+ex pheromones are chemicals the body releases to attract a mate, while putrescine signals danger. The reactions are opposite—putrescine causes avoidance and hostility, whereas pheromones attract.
During the study, participants were unaware they were reacting negatively to putrescine.
“People aren’t familiar with putrescine and don’t consciously link it to death or fear,” note Wisman and Shira.
