Rats! More rodents are infesting cities, as warmer temperatures mean more rat babies

A rat leaves its burrow at a park in New York City on Sept. 17, 2015. Rat infestation in many world cities appears to be soaring, especially in Washington, and a new study blames warming temperatures, urbanization and other human actions. — AP Photo/Mary Altaffer, File

Rat infestation in many world cities appears to be soaring, especially in Washington, and a new study blames warming temperatures, urbanization and other human actions.

A first-of-its-kind examination of trends and reasons in hard-to-count rat populations uses rat sighting reports in 16 cities around the world. In 11 of those cities, rat complaints have increased, according to a study in Friday's journal Science Advances.