The Pittsburgh Zoo & PPG Aquarium is a 77-acre natural habitat that lies within the confines of the city and surrounding development. It is adjacent to a major city
park, Highland Park, which serves as a refuge for all types of wildlife.
Due to large amounts of available food, year-round heated buildings,
and the varied ground cover, there is an unusually high rodent population at the Pittsburgh Zoo. Rodent control is an ongoing concern because of the loss of grain and structure damage these rodents can cause. Mice and rats are also potential vectors of various diseases.