Scientists have revealed that cities all around the world are becoming far rattier with time, and the main reason behind these rodent populations is climate change.
According to CNN, a biology professor at the University of Richmond, Jonathan Richardson, after seeing media reports about the increasing number of rats in the cities, decided to research urban rat trends.
Richardson, along with his team, requested rat data from the 200 biggest cities in the US, but unfortunately they found that only 13 cities have their required quality long-term data. After that, they decided to expand their geographical range and include data from three international cities: Toronto, Tokyo, and Amsterdam.
After analysing the data, the researchers found “significant increasing trends” in 16 out of 11 cities.
As per the study published in the journal Science Advances, the growth rate of rats increased in Washington DC, San Francisco, Toronto, New York City, and Amsterdam, while three cities, New Orleans, Louisville, and Tokyo, saw declines.
The study revealed that there are several reasons for the increasing number of rats in the cities, including high population densities and low amounts of urban vegetation, but the primary reason was warmer average temperatures.
Researchers explained that rats are the mammals whose populations remain limited in the cold, but warmer temperatures, especially during winters, allow them to stay outside longer and reproduce throughout the year.
