There is Only One Kind of Animal That Has Square-Shaped Feces, Isn't It?

Yes, you haven't heard it wrong, nor have you seen it wrong. This block that looks like 'brown sugar' is the excrement of a koala bear.

Excrement belongs to excretion, no matter how small it is, from invertebrates to elephants. Every creature produces excrement, and the shape also has many kinds, such as droplet-shaped (rabbits and sheep), cylindrical-shaped (dogs), and plate-shaped (cows). However, koala bears are unique in this regard because they can excrete block-shaped excrement.

Koala bears are native Australian animals with pouches, stout in body like bears, short and chubby, known for their cute appearance.

They are solitary nocturnal animals, spending their days in underground caves and coming out at night to eat grass and other plants, sleepy,

They sleep an average of 16 hours a day.

Due to the nocturnal nature of koala bears and their poor eyesight, they rely on their sense of smell to navigate and find food.

So, what is the use of 'excrement'?

Various species have adapted to use excrement in different ways, such as spreading seeds or serving as food sources for animals like the dung beetles.

Excrement can also provide information. Different materials, sizes, shapes, and smells can help identify animal species, and using this information can also be used to investigate elusive animals, such as we can study dinosaur excrement fossils to study dinosaur living habits.

However, excrement is also smelly, so it can be used for communication and marking territory.

Koala bears have a strong territorial consciousness, so they use block-shaped excrement to mark their territory to avoid conflicts.

Koala bears can pull out 80 to 100 block-shaped excrement in one night, each with a diameter of about 2cm. Koala bears are very obsessed with their own excrement, they collect it and put it in places where other koala bears can easily find it, such as outside caves, rocks and logs.

This includes information such as 'Who lives here? Are there strangers nearby? Do we need to guard against enemies? Is the female koala bear in estrus?' You can know everything by smelling the excrement.

Most importantly, the cubic excrement is an advantage, its unique shape ensures that it can be stacked one by one without rolling.

But how are block-shaped excrement produced?

Koala bear excrement is square-shaped, obviously not because its anus is square.

First, it's related to its digestive tract.

Koala bears have a very long digestive tract, and the digestive process is very long and slow, generally 14 to 18 days, which allows the intestines to absorb as much nutrition and moisture as possible from the food, resulting in very dry and compact digestive matter.

Secondly, koala bears' intestines have different elasticity.

Scientists conducted experiments on dead koala bears, they emptied their intestines and inflated them, they found that the pressure experienced by the excrement from the beginning to the excretion increased significantly, from the initial 20% to 75%, which is different from the elasticity of the pig's intestines, so the excrement cannot continue to maintain cylindrical shape.

Thirdly, scientists found that the first part of koala bears' intestines has a horizontal, segmented structure, these segmented structures may shape the excrement into cubes, while the last part of the large intestine is relatively smooth, which can maintain the cubic shape.

In general, the segmented structure and the compacting properties of the excrement prevent the intestines from shaping the excrement into a more common tubular shape.