Is A Koala’S Primary Diet Composed Of Eucalyptus Leaves?


Koalas and Eucalyptus Leaves

Koalas are known for their strong association with eucalyptus trees, which make up the majority of their diet. Eucalyptus leaves are low in protein and high in fiber, which can be challenging for koalas to digest. However, koalas have evolved specialized adaptations, such as a unique detoxification system in their liver, to cope with the toxins present in eucalyptus leaves. This close relationship between koalas and eucalyptus trees is not only a dietary preference but also a crucial aspect of their ecosystem.

The Nutritional Composition

Eucalyptus leaves provide koalas with essential nutrients, including water, fiber, and various secondary compounds. While eucalyptus leaves may not be highly nutritious in terms of energy content, they are crucial for meeting a koala’s water and fiber requirements. Additionally, the secondary compounds in eucalyptus leaves serve various purposes, such as deterring herbivores and providing some antimicrobial properties. These nutritional aspects highlight the intricate balance that koalas have evolved to thrive on a diet primarily consisting of eucalyptus leaves.

Behavioral Adaptations

Koalas have developed specific behaviors to optimize their consumption of eucalyptus leaves. They carefully select leaves based on their nutrient content and freshness, often preferring younger leaves over mature ones. Koalas also have a slow metabolism and spend a significant portion of their day resting to conserve energy, allowing them to efficiently digest their fibrous diet. These behavioral adaptations showcase the evolutionary prowess of koalas in maximizing the nutritional benefits from their primary food source, eucalyptus leaves.


1. Gordon G. L. et al. (2010). Digestion of Eucalyptus foliar amino acids in the koala (Phascolarctos cinereus). Wildlife Research, 37(2), 163-168.

2. Marsh K. J. et al. (2007). Effects of natural plant toxins on the koala (Phascolarctos cinereus) immune system in vitro. Australian Journal of Zoology, 55(4), 235-240.

Elena Mars

Elena writes part-time for the Scientific Origin, focusing mostly on health-related issues.