Koala Teeth: Everything You Need to Know

Although they are sometimes referred to as koala bears, koalas (Phascolarctos cinereus) are actually herbivorous marsupials that are endemic to the eucalyptus forests of Australia. Koalas sleep between 18 and 22 hours a day. This extended sleep is necessary because their diet consists of low-nutrient, high-fiber eucalyptus leaves, which are difficult to digest. Prolonged sleep allows the koala to conserve the energy needed for digestion. Although koalas can digest eucalyptus leaves due to a special digestive system, these leaves are toxic to humans and most other animals. However, koalas have evolved to take advantage of this abundant food source with little to no competition. So, what type of teeth are required to gnaw these tough, fibrous leaves? Continue reading to discover everything you need to know about koala teeth.

What Kind of Teeth Do Koalas Have?

Koalas have a gap between their incisors and premolars called a diastema. This large, natural space is located between the sharp front teeth (incisors) and the back teeth (premolars and molars). The diastema is a key adaptation for their diet of tough, fibrous eucalyptus leaves, as it allows the koala’s muscular tongue to efficiently move large amounts of leaves around the mouth.

Leaves are first stripped from branches using the koala’s sharp incisors. The diastema allows the collected foliage to be held and oriented properly before it is shifted to the powerful molars at the back of the mouth for thorough shearing and crushing.

This dental arrangement is a result of evolutionary changes linked to Australia’s drying climate during the Miocene period, when the decline of rainforests led koala ancestors to adapt to a eucalyptus-based diet.

How Many Teeth Do Koalas Have?

Koalas typically have 30 teeth. Their front teeth, or incisors, are sharp for snipping leaves, while their back molars are used for crushing and shearing the leaves.

The upper jaw contains three incisors on each side, with the two closest to the center meeting the lower incisors when chewing. The outer two are slightly larger. The koala’s lower jaw has two large, forward-pointing incisors that are used to nip leaves from branches. The lower jaw is devoid of canine teeth but has four molars on each side.

The dental formula for koalas is: Incisors 3/1, Canines 1/0, Premolars 1/1, Molars 4/4 = 30. This formula shows the number of each type of tooth on one side of the upper and lower jaws.

Koalas are diprotodonts, a group of marsupials that also includes wombats, kangaroos, and phalangers. As diprotodonts, koalas have fewer than three upper incisor teeth on each side of their jaw.

Are Koala Teeth Sharp?

The koala’s front teeth, or incisors, are sharp and can snip leaves, while their molars are designed to crush their food before swallowing. However, these teeth are not sharp enough to pierce meat or cut through prey.

According to a 2002 study published in the Australian Journal of Zoology, a koala’s teeth wear down over their lifetime from chewing tough eucalyptus leaves. Eventually, their teeth can become so worn down that they can no longer eat properly, which often leads to their starvation. This is why tooth wear is often used by wildlife staff to estimate a koala’s age. 

Do Koalas Bite Humans?

Koalas rarely bite humans, except for wildlife professionals and others who work with koalas regularly. A koala would only bite a human if it believes it is being threatened, and even then, it is more likely to hiss, snarl, or grunt as a warning, or lash out with its claws.

Koalas prefer to avoid conflict and climb higher in trees to escape human interaction. Biting or using their sharp claws to inflict harm is generally a defensive last resort when they feel cornered or scared.