Countries With More Cats Are Happier and Somehow Have Less Toxoplasmosis

Cat-rich countries tend to be happier, while Toxoplasma exposure points the other way.

Cats inhabit a unique place in human life. They curl up on our beds, stalk through our gardens, and, in some cases, carry a parasite capable of spending years inside the human body.

Now researchers have found an equally peculiar pattern at the scale of entire countries: places with more cats tend to report greater happiness. Yet those same cat-rich countries tend to have lower levels of Toxoplasma gondii exposure, the parasite for which cats serve as the definitive host.

Cats rule the world

From ancient societies that revered them to modern cities where they thrive alongside humans, cats have mastered a rare trick: becoming deeply dependent on us without ever quite seeming domesticated. But there’s still much we don’t know about our furry feline friends.

The findings come from a new study that compared 93 countries using measures of national happiness, cat abundance, GDP, income, health spending, and Toxoplasma exposure.

It’s an intriguing result, but not evidence that cats make people happy—or that the parasite makes them miserable. Instead, it reveals a country-level pattern whose explanation may have as much to do with wealth, sanitation and pet-keeping practices as with cats themselves.

And wealth seems to be particularly important.

National happiness was strongly correlated with cat density. On a correlation scale where 0 means no relationship and 1 means a perfect positive relationship, the two scored 0.62. vcBut wealth showed an even stronger connection. The correlation between happiness and GDP was 0.80, while cat density and GDP scored 0.79.

In other words, richer countries tend to be happier, and they also tend to have more cats per person. That makes it difficult to tease apart what, if anything, the cats themselves are telling us.

That makes it difficult to tease apart what the cats themselves might be telling us.

Why More Cats Don’t Necessarily Mean More Toxoplasma

To make the comparisons, the researchers calculated estimated domestic cats per 10,000 people. Happiness scores represented averages from 2022 through 2024.

For Toxoplasma, however, they had to take a less direct route. They used infection estimates among pregnant women from a 2020 global meta-analysis as a proxy for population-wide exposure. Those estimates drew on studies conducted over several decades.

The data produced a counterintuitive pattern. Countries with greater happiness tended to have less Toxoplasma exposure, while cat density showed a weaker negative relationship with chronic Toxoplasma exposure.

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That sounds really strange. After all, cats are central to the parasite’s life cycle.

Felids are the definitive hosts of T. gondii, meaning the parasite reproduces sexually in their intestines. Infected cats can shed oocysts in their feces, which can contaminate soil, water and food. Humans can also acquire the parasite by eating undercooked infected meat. But simply counting cats doesn’t tell us much about how those cats live.

A well-fed indoor pet receiving veterinary care is epidemiologically very different from a free-roaming cat that hunts prey. Wealthier countries may have more household cats while also having better sanitation, more commercial pet food, better veterinary care and fewer opportunities for parasite transmission.

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The researchers couldn’t test that explanation directly. Their cat data do not distinguish household pets from stray or feral animals. The analysis also did not account for potentially important differences in urbanization, climate or sanitation infrastructure.

Not a Happiness Prescription

A 2022 systematic review of 24 studies found that pet ownership was sometimes associated with less loneliness or social isolation, particularly during the COVID-19 pandemic. But many of the studies found no significant relationship.

Likewise, a 2016 study of pet ownership and happiness found that pet owners reported greater life satisfaction than nonowners, but not better outcomes on several other measures of well-being.

There is precedent on the parasite side, too. A 2021 JAMA Psychiatry meta-analysis involving more than 13,000 healthy people linked Toxoplasma seropositivity with slightly poorer performance in several cognitive domains. The effects were small, however, and observational research cannot establish that the parasite caused them.

The same caution applies even more strongly to the new study. A country with many cats is not evidence that an individual cat owner will be happier. Nor can the analysis tell whether cats contribute to well-being or simply flourish in societies where people already have more money, security, and resources.

“What we find most interesting is that these results bring together factors that are usually studied separately: wealth, health, human–animal relationships and infectious disease,” the researchers said.

In other words, cats may not be making nations happier. But their abundance—and the conditions under which people live alongside them—could be another small window into what prosperous, healthy societies look like.

The study was published in the journal PLOS One.