Roof rats are primarily nocturnal. They forage for food in groups of up to ten and tend to return to the same food source time after time. These rats follow the same pathway between their nest and food.
Roof rats live in colonies and prefer to nest in the upper parts of buildings. They can also be found under, in and around structures.
Roof rats secured their place in history by spreading the highly dangerous bubonic plague. Though transmission is rare today, there are still a handful of cases in the U.S. each year. Roof rats can also carry fleas and spread diseases such as typhus, jaundice, rat-bite fever, trichinosis and salmonellosis.