Chicago named rattiest city for 9th year in a row -- here's how to get a free t-shirt to mark the occasion

For the ninth consecutive year, the Windy City has been deemed the rattiest city in the United States, according to Orkin's Rattiest City List. 

Los Angeles claimed the number two spot this year with New York coming in at third place.

In addition to bragging rights, Chicagoans can also claim a free t-shirt to commemorate the title.

According to Orkin, mice and rodents invade an estimated 21 million homes in the United States. Typically, rodents will enter homes between October and February in order to shelter from the cold and search for food and water. 

"Rodents multiply swiftly and when an infestation is left unattended, they can cause extensive damage to homes and yards," said Ben Hottel, an Orkin entomologist. "Rats are capable of squeezing into spaces through holes as small as a quarter, which makes it especially important to seal cracks from the outside."

In addition to causing structural damage to homes, rodents can also cause health issues. For more information about rodent prevention, click here.

For the full list of top rattiest cities, click here.