If you live in a U.S. city, you've likely seen a rat or two running around. According to the pest control company, Orkin, an estimated 21 million U.S. homes face rodent invasions, each fall.
But rats play a much larger role in human history. These creatures have been sacrificed for the advancement of scientific research.
Rats are complicated — and it inspire equally complicated feelings in us.
This year, New York City held its first ever annual national urban rat summit to address the city's chronic rat problems.
Rats pose real health and safety risks to human, we discuss what we lose by only seeing them as pests.