Copyright 2025 The Associated Press. All Rights Reserved. A rat leaves its burrow at a park in New York City on Sept. 17, 2015. ( AP Photo/Mary Altaffer, File) A rat ...

An extra month may not sound like much, but female rats can have a litter every month. Each litter is eight to 16 baby rats, Richardson said: “That is a recipe for accelerated population growth.” ...

An extra month may not sound like much, but female rats can have a litter every month. Each litter is eight to 16 baby rats, Richardson said: “That is a recipe for accelerated population growth.” ...

FILE - A rat leaves its burrow at a park in New York City on Sept. 17, 2015. ( AP Photo/Mary Altaffer, File) ...

WASHINGTON (AP) — 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.