Regardless of political affiliation, “the brown rats of New York are struggling just as hard (as humans) to adapt to urban existence.”


Long before COVID-19, Rattus norvegicus had been cleared of history’s major charge: the Black Death was spread by humans not rats.

They got a bum rat.

The ostensible reason for this post? Vindication for the rat, but scroll down for the subsidiary purpose.

Rats have other problems now.

Beer and bagels please: New York rats evolve to mirror human habits, by Robin McKie (The Guardian)

Changes in rodents’ DNA means they are now prone to similar health threats to humans, scientists discover

Humans are not alone in suffering from the stresses of modern city life.

Researchers have found the brown rats of New York are struggling just as hard to adapt to urban existence.

Indeed it is possible, they say, that both humans and rats have undergone parallel shifts in their genetic make-up in response to city life, leaving them prone to similar health threats, such as the effects of pollutants and the consumption of highly sugared foods.

“We know rats have changed in incredible ways in their behaviour and in their diet, just as human communities have changed,” said Arbel Harpak, a population geneticist at the New York’s Columbia University. “In New York you can see them eat bagels and beer; in Paris they like croissants and butter. They adapt in amazing ways.”


The crucial point, say the researchers, is that urban rats are so closely associated with human city-dwellers that it is possible similar genetic changes have occurred in both species. “Like humans, rats live in higher densities in cities, leading to increased pathogen transmission potential,” they argue. “In addition, mosquito species that have rapidly invaded urban areas across the world feed on both rats and humans – suggesting a novel, shared-disease exposure.”

The most striking common feature of the lives of urban humans and urban rats is diet, the researchers discovered: both consume an increasingly large amount of highly processed sugars and fats. Such a diet leads to various health concerns, which could also apply to rats.