Koalas' Small Brain

Koalas have unusually smaller brain. In fact; it wouldn't be wrong to say that the Koalas have one of the smallest brains (proportion to skull cavity) in the animal kingdom (mammals). The zoologists and the animal researchers who have worked on the koalas have concluded that the koala's brain roughly comprises of 60% volume of their overall skull cavity. On the other hand; almost all the animals have a brain volume of more than 60% within their skull cavity.

Koalas have one of the smallest brains within the animal kingdom. A Koala's brain is almost 60% volume of the total skull cavity.

The size of a brain also reflects the intellectual ability of an animal as well. Since the koalas have smaller brains while the sizes of the brains demonstrate the intellect of an animal, therefore, the koalas should not be assumed one of the good examples in this regard. On the positive side; the koalas have exploited their smaller brains to their own advantages. Let's list down all such advantages and further explore the life of this mysterious animal i.e., the Koala.

Koalas have one of the smallest brain (proportion to the skull size) within the animal kingdom.
Koalas have one of the smallest brains within the animal kingdom. A koala's brain comprises of just 60% of the total skull volume. Photo courtesy of  

Koalas
Smallest Brain in Animal Kingdom Brain Size
60% of Skull Volume Animals with Small Brain
Less Intellectual Koalas
Lack Intellectual Abilities Koalas Exploit Brain
Smaller Brain to Advantage

Koalas have a smaller brain.
Koalas have a smaller brain. A smaller brain of Koala also means that it has limited intellectual scope to understand its environment. This picture belongs to  

One of the biggest exploitative advantage which the koalas derive because of their smallest brain is the energy conservation. Their tiny brain really helps them in this regard and the energy stays retained within their bodies as their metabolism goes to the lowest levels. Usually within the body of any organism, two of the body organs namely the brain and the liver utilize maximum levels of energy. The bigger the size of these organs within an organism the larger the amount of energy is consumed and vice versa.

Koalas smallest brain helps them to conserve their body energies. Remember the energy levels within the koalas is very low because of their diet i.e., Eucalyptus leaves.

The koalas conserve their body exactly in the same manner. Conserving the body energy is very necessary for the koalas because the diet which they eat (Eucalyptus Leaves) is very high in fiber (almost 6 times the bread fibers) and very little in energy. Therefore; the koalas' smaller brain really works as a magic for them and helps them not only to conserve but to retain the energy levels within their bodies.

Koalas' small brain helps them to conserve body energy.
Koalas' small brain helps them to conserve the body energy. Photo courtesy of  

What appears to be a drawback; the koalas' lifestyle converted it into an advantage.

Koalas smaller brain slows Koalas' metabolism rate.
A smaller brain of the Koala will also mean that a Koala will have a slower metabolism as well. This picture belongs to  

Another big advantage which the koala extracts from its smaller brain is it protects them against any serious head injury if they fall from the trees. Since the koalas' skulls are bigger while their brains are smaller, the rest of the areas within their skulls are not empty or hollow. Nature has filled this area with a special fluid that serves as a protective shield from any hardcore external impact.

Koalas have a special fluid in their skulls which surrounds the brain and protects them from any hardcore impact of falling down from the trees or any other injury.

Therefore; this fluid acts like an internal (invisible to the out world) helmet for the koalas. There is no doubt that the koalas spend their whole life on the trees and they are one of the true arboreal of Australia. However; occasionally they do fall from the trees and their smaller brain stays safe from any serious injury because of this special fluid surrounding the brain within their skulls.

Koalas' small brain protects them against any head injury.
Since koalas brain is very small as compared to its skull size but rest of the area within the skull is not empty. It is filled with some flouid which helps koalas against any kind of a head injury. Photo courtesy of  

Nature has blessed koalas with extra head protection by insulating a protective fluid inside their head.

Koalas brain has limited capabilities.
Koalas have unusually smaller brains, this also prompts key questions about the capability of their brains. Usually Koalas have limited brain capability and they are not considered as smart creatures. This picture belongs to 

Another advantage for a koala to have a smaller brain is that koala does not have to eat much. Koalas are even known to survive extreme droughts as well. Smaller brain means a slower metabolism and as mentioned earlier less consumption of body energy. Herbivores are known to destroy the wild plantation as they usually sleep less and spend the whole day in grazing. But koalas who eat Eucalyptus are not even a threat to any plantation as they sleep for more than 20 hours per day and only eat for a small time.

Koalas' smaller brain also allows them to consume less amount of food. Because of the smaller brain, its metabolism and energy requirements are both low, therefore, it can even survive with a little availability of Eucalyptus leaves.

Eucalyptus leaves are very high in terms of fiber. After eating a small quantity of leaves, a koala's stomach becomes full and therefore; it stops eating and goes for a rest or sleep for more than 20 hours per day. Koalas metabolic rate is also very slow, therefore; they don't need any instant energy requirements for their normal day life.

Koalas small brain allows them to eat less.
The smaller brain of the koalas allows them to have lower metabolism and lower levels of body energy needs. Consequently they survive even by eating less. Photo courtesy of  

Despite the smallest of brains within the animal kingdom, the koalas have developed a good sense of smell. Their sense of smell is so much advanced that they can successfully distinguish fresh leaves from the other ones, Eucalyptus leaves and their kinds, levels of nitrogen within the leaves availability of water within the leaves and the levels of toxicity etc.

Despite the smallest of brains, the koalas possess a great sense of smell which helps them to choose the best leaves as part of their dietary lifestyle.

Since koalas drink little or no water at all, therefore; they are totally dependent on the leaves for their water requirements too. In this case their sense of smell help them to choose the leaves that have maximum (more than 50%) contents of water. These are one of the key reasons that the koalas are also termed as the finicky eaters within the animal kingdom. Lastly; the male koalas also scent mark their trees and the other rival male koalas are able to identify those scent markings on individual basis through their sense of smell.

Koalas have small brain but good sense of smell.
Despite the fact that the koalas have smaller brain within the animal kingdom, they still have a good sense of smell. Photo courtesy of  

Lastly; if we extract the negatives because of the smaller brains within the koalas, we shall notice that they are pretty hard to find. Koalas may tend to be slow and sleepy, koalas may stick to their lifestyles and may not be tamed for a new one, they stick to only one kind of a diet (Eucalyptus leaves), they may not be much aware of the aerial predators etc. But many other animals tend to have these negatives too.

There are almost no negatives for koalas for having smaller brain. The koala have thrived with the smallest of brain for millions of years and will continue to do so.

Recently; only the human intervention have threatened their lifestyle but otherwise this animal even with the smallest of brains have been able to survive for millions of years and will continue to do so. Therefore; there are no negatives but rather positives which it takes from having a smallest of the brains within the animal kingdom.

Koalas have small brain but they have thrived for millions of years.
Koalas have smaller brain and the researchers have pointed some lackings of koalas because of that yet still the koalas have thrived at the continent of Australia for millions of years. Photo courtesy of