Here's why:
* Diet: Koalas are highly specialized feeders, almost exclusively relying on eucalyptus leaves as their food source. They have evolved unique digestive systems to cope with the toxins and low nutritional content of eucalyptus.
* Habitat: They are adapted to live in specific eucalyptus forests, requiring a certain type of tree and climate.
* Reproduction: Their reproductive rates are slow, with females giving birth to only one joey at a time.
These factors make koalas vulnerable to changes in their environment, such as habitat loss, bushfires, and disease.
Let me know if you'd like to know more about specialist species!