Over time, the Koala has evolved several physiological adaptations that allow them to be one of the three animals that can survive when they eat the Eucalyptus leaves. The Koala has evolved to cope with this high fibre, low protein diet. The koala has adapted to utilize Eucalyptus as a sole source of nutrition. To other animals Eucalyptus leaves are extremely fibrous and low in nutrition, and are poisonous. Koalas are fussy eaters and have strong preferences for various types of eucalyptus leaves. To cope with this poorly balanced diet, koalas have evolved many specialized adaptations.