Rats are on the rise. Here’s what cities are doing about it

Climate change has brought longer stretches of warmer weather, which means more time for breeding.

Rats are, “a thing of beauty in many different ways,” Bobby Corrigan said, and “as a mammal, it’s a very successful mammal” The most common rat species in the United States , the Norway rat, first came to the country around 1775 .

Globally, a number of countries have pushed rat eradication in recent years .

New Zealand has pledged to rid itself of all rats by 2050 .

Alberta , Canada , has been rat-free since 1950 thanks to rat control program.

For all the negatives, rats do have an upside: They have added 25 to 30 years to humans’ longevity as a species.