Why do rats approach people before death? - briefly
Rats are drawn to the altered body odors and diminished defensive responses that occur in individuals nearing the end of life, which signal an easy source of food and shelter. These cues increase the probability that rodents will approach and remain near the person.
Why do rats approach people before death? - in detail
Rats are attracted to individuals who are close to death because physiological changes in the body emit cues that signal an easy food source. As a person’s health declines, metabolic processes slow, and the body produces higher levels of carbon dioxide, ammonia, and volatile organic compounds associated with tissue breakdown. These chemicals are detectable by the highly sensitive olfactory systems of rodents, which interpret them as indicators of carrion or weakened hosts.
The animal’s foraging strategy is opportunistic. In natural environments, rats locate dead or dying prey by following scent trails of decay. When a human exhibits similar chemical signatures, the rodents respond with the same investigative behavior. Laboratory studies have shown that rats can be trained to move toward sources of specific aldehydes and ketones released during tissue necrosis, confirming the role of odor cues.
Stress hormones released by a dying individual, such as cortisol, alter skin secretions and breath composition. These hormonal by‑products can further enhance the attractiveness of the host to rodents, which are known to seek out environments rich in nitrogenous waste. Additionally, weakened immune defenses reduce the production of antimicrobial peptides on the skin, creating a less hostile surface for bacterial growth. The resulting increase in bacterial activity contributes to a stronger odor profile, reinforcing the rats’ attraction.
Observational reports from hospice facilities and hospitals note a higher incidence of rodent sightings in rooms where patients are in the final stages of illness. While systematic epidemiological data are limited, anecdotal evidence aligns with the biological mechanisms described above. Researchers caution that environmental factors—such as building sanitation, waste management, and proximity to sewer systems—also influence rodent presence, making it difficult to isolate the effect of human physiological changes alone.
In summary, the convergence of elevated decay‑related odors, increased carbon dioxide output, altered hormonal secretions, and reduced antimicrobial defenses creates a chemical environment that draws rats toward individuals approaching the end of life. The behavior reflects the species’ evolutionary adaptation to locate and exploit vulnerable food sources.