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What Mammal is Considered the Dumbest of All?

Humans and all other warm-blooded vertebrates with hair are classified as mammals. They are viewed as much smarter than other animal species since they have more advanced brains. But did you know that not all mammals are actually as intelligent as they seem to be?

Koalas have a smooth brain with lower levels of distinction and understanding than many other animals. If you gather Eucalyptus leaves and place them in front of them, they would be completely clueless about what to do.

What is a Koala?

The koala’s scientific name, Phascolarctos cinereus, loosely translates to ash grey pouched bear. They are commonly found in Australia and can live up to 20 years. This tree-climbing mammal, also known as a bear, is actually classified as a marsupial. Marsupials are mammals that have a pouch for offspring development.

Though koalas appear fuzzy, their hair is similar to coarse sheep wool. They have two opposing thumbs on each hand, and their feet and hands have rough pads and claws for grasping onto branches. They have two fused toes on their feet to comb their fur.

Apart from primates, koalas are one of the few mammals with fingerprints. Koala fingerprints are so similar to human fingerprints that it can be difficult to tell them apart. (Source: National Geographic)

Why is Koala Considered the Dumbest Mammal of All?

The koala has one of the most inferior brain-to-body mass ratios. Even though koalas are illiterate, they have survived because their brains consume very little energy. 

The brain of a koala is smaller than that of other marsupial brains, accounting for about 0.2 percent of its body weight. A slim brain may save the koala energy, which it doesn’t have much due to its nutrient-deficient diet.

Its hemispheres sit like a pair of shriveled walnut halves on top of the brain stem, in contact neither with each other nor the bones of the skull, Koalas might be cute, but what’s inside the skull doesn’t sound very impressive.

Tim Flannery, Australian Scientist

Koalas are not exceptionally bright. They use as little energy as possible, sleeping approximately 18-22 hours per day. They move slowly and deliberately from their sleeping spot to their food source and back. 

Regrettably, they don’t appear to be able to adapt well to moving cars or the dangers of crossing highways and close to populated areas (Source: Bio Geo Planet )

Why Do Koalas Sleep Too Much?

Koalas are found in eucalyptus forests in southeastern and eastern Australia. When they are not sleeping, they are usually eating. They rely on the eucalyptus tree for habitat as well as food. Koalas can devour up to a pound of eucalyptus leaves per day. Because eucalyptus is toxic, the koala’s digestive system has to work hard to break it down and extract the limited nutrients.


That’s why koalas sleep so much, their diet provides very little energy. Koalas can sleep for 18 to 22 hours in forks or nooks in the trees. Koalas rarely drink water because they get most of their moisture from these leaves. Koalas can even hold leaves in their cheek pouches for later consumption. They consume so much eucalyptus that they frequently smell like it. (Source: National Geographic)

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