Complaints about rats in New York City almost doubled between 2010 and 2017, and one rat expert thinks the population explosion may be linked to climate change.
Robert Corrigan, a rat expert, told Popular Science that the rodents stop mating when winter is coming because food is scarce and temperatures are low. Warmer winters in recent years may have given rats the opportunity to have more litters than usual.
Corrigan, who has consulted with New York City on the city’s rat extermination efforts, pointed out that there is no definitive scientific evidence linking climate change to an increase in rat reproduction. But he said even a small change can go a long way toward increasing the rats’ reproductive abilities.
New York City logged a record high number of rat complaints in February 2017 when the average temperature was seven degrees higher than the historic average for February.
With the four warmest years on record happening in the last four years, Corrigan warns increased rat reproduction could be the new normal.