Preference for Clear versus Distorted Viewing in the Chimpanzee

Abstract
Molybdenum-fed rats housed in galvanized cages gained less weight and had lower hemoglobin levels than similarly fed rats housed in stainless steel cages. Since similar effects were produced in rats housed in stainless steel cages by increasing the zinc in their diets, it was concluded that zinc consumed by chewing on zinc-coated cages was responsible for the abnormalities noted.