Cat Density Linked to National Happiness in 93-Country Study
An international study finds countries with more pet cats per capita report higher happiness levels.
Countries with more pet cats tend to report higher national happiness. A new study analyzing data from 93 nations also found that greater exposure to the cat-borne parasite Toxoplasma gondii correlates with lower happiness levels. Published in PLOS One, the research reveals a surprising ecological link between domestic cat density, parasite prevalence, and subjective well-being.
The study, titled 'Wealth, health, cats and Toxoplasma gondii: An ecological correlational study of subjective well-being across 93 countries', examined national income, healthcare spending, GDP, pet cat density, and Toxoplasma gondii prevalence. It confirmed that countries with a large number of pet cats do not necessarily have higher toxoplasmosis infection rates. In fact, they often have lower prevalence. China presented an interesting case, registering a relatively high happiness score despite having lower cat density than most nations.
How wealth and cat care shape disease risk
Wealthier nations show a distinct pattern in pet management that influences disease risk. In these countries, cats are more likely to be kept indoors, receive regular veterinary check-ups, and be fed commercial pet food. This controlled environment reduces their exposure to Toxoplasma gondii and lowers the transmission risk to humans.
In contrast, cats in low- and middle-income countries are often allowed to roam freely. This increases their likelihood of infection from wild sources. The research team suggested that Toxoplasma transmission from cats to humans may therefore be higher in these regions. Veterinary care access and pet management practices emerge as key factors linking wealth, cat ownership, and health outcomes.
Understanding the parasite and its effects
Toxoplasma gondii is a widespread parasite, infecting an estimated one-third of the global population. Cats are its primary host. For most healthy people, the infection is clinically asymptomatic and harmless. However, it can cause problems in more vulnerable groups and has been linked to anxiety, depression, and schizophrenia.
The study authors emphasize that their findings describe only associations at the country level and cannot be interpreted as causation. They did not prove that owning cats increases happiness or that toxoplasmosis decreases it on an individual level. The complex interplay of factors means national-level trends do not directly translate to personal experience.
Experts call for deeper, individual-level research
Given the correlational nature of the findings, researchers recommend future studies take a more granular approach. They propose tracking cat owners and non-cat owners on an individual basis over time. Future work should integrate socioeconomic and biological perspectives through longitudinal and interdisciplinary methods.
Biologist Javier I. Borráz-León of Mexico's National Institute of Psychiatry commented on the significance of linking typically separate research fields. The research team stated that understanding why some groups report higher well-being requires considering biological and ecological factors alongside the socioeconomic conditions that have traditionally been the focus. The study was fact-checked by science journalist Carly Cassella.
The international team concluded that national well-being is shaped by a web of factors including wealth, health, human-animal relationships, and infectious diseases.
