Countries with more cats scored higher on happiness, with heavy caveats

Cat density explained a large share of the gap in national happiness across 93 countries: the correlation between cats per 10,000 inhabitants and a country’s happiness score was 0.62, and the statistical model that included it accounted for 47% of the variation between nations. The analysis, published September 30, 2026 in PLOS ONE, also found that countries with more recent infection by the cat-borne parasite Toxoplasma gondii scored lower.

Every one of those numbers describes countries, not people. The authors state it themselves: their findings “describe associations at the national level” and should not be used to infer individual-level effects or personal risks related to cat ownership, happiness or parasite exposure. Nothing in the paper shows that a person who gets a cat becomes happier, or that a happy person is more likely to get one.

Cats per 10,000 inhabitants against a Gallup-based ranking

The paper, titled “Wealth, health, cats and Toxoplasma gondii: An ecological correlational study of subjective well-being across 93 countries,” is by Javier Borráz-León, Markus Rantala, Indrikis Krams and Dario Maestripieri. Their affiliations span Mexico’s National Institute of Psychiatry, the University of Turku in Finland, the University of Latvia and the University of Chicago, where Maestripieri works. The study reports no specific funding.

Happiness scores came from World Population Review’s rankings, which draw on Gallup polling data across six categories: GDP per capita, social support, healthy life expectancy, freedom to make life choices, generosity and perceptions of corruption. Those components overlap with wealth by construction, a point that matters when the question is whether cats add anything beyond income. Cat numbers came from a public country dataset of cat populations, converted to cats per 10,000 inhabitants.

Ecological studies of this kind compare group averages, and group averages can behave very differently from the individuals inside them. A country’s cat density is a single number for every resident, only some of whom live with a cat; its happiness score is likewise a national average from polling. A relationship between two such averages can arise even if no individual cat owner is any happier than the neighbor next door, because the averages also carry everything else that distinguishes one country from another.

Wealth, the confounder the authors flag

Richer countries differ from poorer ones in nearly every respect the study measured, and Sci.News reported the paper’s blunt finding on this: happiness correlated strongly with cat density, though it correlated even more strongly with national income and GDP per capita. The regression handled the overlap in an unusual way. GDP was dropped from the final model because it was too entangled with income and the other predictors (a variance inflation factor of 7.61), leaving cat density, health expenditure and parasite exposure.

In that simplified model cat density kept a standardized coefficient of 0.52, while health expenditure showed small, non-significant associations. The authors call cat density and recent-infection rates the strongest independent predictors. “Independent” here means within the model’s variables. Culture, climate, urbanization, religion, pet-keeping norms and the many things a model of 93 countries cannot hold fixed remain outside it.

Toxoplasma and the cat counts themselves

Two caveats from the paper bear directly on how far the central correlation can be pushed.

The parasite finding runs against the cat-lover reading. Recent infection, measured by IgM antibodies, correlated negatively with happiness at minus 0.54, while chronic infection was also measured by IgG. Because wealthier nations tend to have more cats and less parasite exposure, the authors point to differences in cat care, such as indoor, vaccinated, commercially fed cats in richer countries and free-roaming cats elsewhere, a pattern Medical Republic highlighted. The CDC says more than 40 million people in the United States carry the parasite and that most healthy carriers have no symptoms, so a national seroprevalence figure is not a count of sick people.

Two measurement limits sit at the foundation. The parasite data are seroprevalence among pregnant women, used as a stand-in for entire populations, which the authors acknowledge may not represent everyone. And the cat-population dataset, in the authors’ words, conflates pet cats, stray cats and feral cats, so it is not a count of household pets. A country with many street cats and a country with many sofa cats can post the same density, which makes cats per 10,000 inhabitants a blunt stand-in for anything about household life, and the happiness side of the comparison is a ranking built from polling rather than a direct survey of pet owners.

The result is a pattern across 93 national averages that survives the authors’ modeling choices and still falls short of showing cause in either direction. Wealth is the obvious shared driver of cat numbers, health spending and happiness scores alike. Whether cat density tracks happiness within a country’s own regions or households is a question this dataset has no way to answer.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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