Animals are as extraordinarily diverse as they are wondrous.
Our job at learningmole.com is to unveil some of these wonders and show everyone, ourselves included, a glimpse of how majestic the animals we live side by side with are. That is why we have dedicated a series of articles to discuss and learn about some animals’ awe-inspiring organs.
In part one of this series, we introduced three amazing organs whose composition and the way they function are just miraculous. First, we discussed the giraffe’s elongated neck. We learned a little about its anatomy and explored two theories that explain its evolution.
Then, we moved to the cat’s sensitive whiskers, which are incredibly vital for the cat to survive. After that, we learned why the rabbit has such long ears and in what way they assist in its protection from predators and maintaining a suitable body temperature.
In this article, we are going to continue this incredible journey with animal adaptations by introducing two more organs that belong to two other fantastic animals. Although they might look eccentric on the outside, their internal structure and how they are used are super unique, literally jaw-dropping.
So let’s hop into it.
The elephant is a highly distinguished animal for having numerous extraordinary things. It is one of the most intelligent mammals, standing alongside humans, dolphins, monkeys, chimpanzees and octopuses.
This high level of intelligence is made available by the elephant’s brain. It is three times as large as our brain with over twice as many neurons as we have—257 billion neurons compared to our 120 million.
That means elephants have much more brain activity, which in turn boosts their intelligence. An example of this is some elephants’ ability to solve problems and use tools. In addition, elephants have shown a remarkable ability to remember things, places, and people even after a long period of time.
On the outside, the elephant is also distinguished by its many eccentric organs and body parts. For instance, it has hoofless, paw-less, and claw-less legs that are also cylindrical, flat and super sturdy to support the elephant’s giant body.
The ears are broad, heart-shaped and fan-like. The tusks are strong, sharp, deeply rooted, curled and made of ivory. And let’s not forget about the elephant’s long, strong trunk, which we are more concerned about in this part of the article.
Scientists do not know for sure why elephants evolved such long trunks. Some say that their ancestors that existed on Earth millions and millions of years ago had no trunks at all. Yet, for some unknown reason, they developed them over time.
Charles Darwin, the great English naturalist who revolutionised our understanding and perception of nature, believed that elephants developed trunks due to their need for food.
According to him, the elephants’ ancestors did have trunks, but they were short. Then during times of drought and food scarcity, when there was little to no food or water within reach of their short trunks, they had to grow them longer and longer. This way, they could reach high tree branches.
Instead of grazing, elephants gradually started browsing. Consequently, new generations with longer trunks began to emerge.
Anyways, now we have elephants with long, robust trunks. So let’s take a look at how majestic this organ is.
The elephant’s trunk is basically the nose and upper lip joined. This only happens right before birth. But while the baby elephant is still forming inside its mother’s womb, these two organs, the upper lip and nose, are usually separated.
The trunk typically grows to 1.83 cm and can sometimes reach a length of 2.1 cm. It can weigh up to 140 kg, which is at least 20% of the elephant‘s total body weight. In some elephant species, which are so majestically large, the trunk grows to weigh 317.5 kg!
The composition of the trunk is also distinct, for it was designed to support so many survival functions. First of all, it has no bones at all and little to no fat. It is very muscular, comprising 40,000 muscles and a total of 150,000 separate bundles of muscle fibres, scientifically known as muscle fascicles.
Directly connected to the elephant’s skull, these muscles are divided into two main groups that work together in harmony. The first is the surface muscles found on the upper side of the trunk, under which is the second group, the internal muscles.
Within this fantastic structure, there is also a massive bundle of 400,000 nerves that control the elephant’s trunk. The primary nerve of this bundle, which runs through the trunk, is three times as thick as the elephant’s optic nerve.
This network of nerves makes the trunk very sensitive and intensifies the elephant’s sense of touch. Just at a single tender press, a tremendous amount of information is carried through these nerves to the brain, allowing the elephant to learn about its surroundings and get better vision and perception of the environment.
In fact, it is not just the trunk that is very sensitive but the entire elephant’s skin, despite being so thick. The elephant can feel the pressure of anything as light as a fly landing on any part of its body.
Basically, the elephant uses its enormous trunk to do a whole set of functions, on top of which is breathing, which makes a lot of sense since the trunk is part nose, part upper lip. Secondly, as mentioned, the elephant uses its trunk to touch and recognise things and explore the surroundings. The third is the olfactory function, commonly known as smelling.
The elephant smells (and breathes) through the nostrils found at the tip of the trunk. Surprisingly, the elephant’s sense of smell is so strong. Sometimes, it is even estimated to be four times as strong and sensitive as that of the dog. Moreover, the elephant can smell food that is several kilometres away.
I wonder if it is the elephant’s colossal size that did not get it enrolled in the police force!
Additionally, elephants can move their trunks in different directions. With no bones at all, elephants can curl their trunks and twist them from right to the left and from left to right. They can move them upward to reach seven-metre-high leaves and downward as deep as to dig in sand or mud. Trunks are also used in fights and wrestling.
Because they have an incredible number of muscles, trunks are so strong that they allow the elephant to uproot trees and lift them up. Trunks can carry things as heavy as 350 kg.
Furthermore, elephants use their trunks to grab things and hold on tight to them. If what they hold happens to be food, they curl their trunks inward to move the food to their mouths. Elephants also use their trunks for drinking and showering. In fact, the trunk is capable of holding between 7 and 8.5 litres of water.
If elephants go underwater, they keep their trunks above the water to breathe, just like a snorkel.
According to the dictionary, the pouch is a flexible bag used to store things.
Although it is not a very common organ, many animals do have pouches. Take, for instance, squirrels and chipmunks. They have pouches in their mouths, which enable them to store as many walnuts as possible. Koalas also have pouches where they keep their babies.
Yet, the pouch we are concerned about here is that of the kangaroo, well, the female kangaroo. Although it does work like the womb found in all female mammals, this pouch is pretty distinct not just in its structure but in how it works as well.
Only female kangaroos have pouches, which makes a lot of sense since they are responsible for reproduction. And because of this very function, the kangaroo’s pouch is highly complicated; designed in a way to provide everything the foetus needs to grow into a fully developed baby kangaroo.
But before we get any further, we need to look into the kangaroo’s reproduction cycle to understand how significant this pouch organ is.
When a male and a female kangaroos mate, the egg is fertilised. So it moves to the womb and stays there for 33 days. During this period, this fertilised egg develops into a tiny little foetus called joey—not Joey from the famous American sitcom Friends!
The joey is highly underdeveloped, blind and deaf. It does not weigh more than 1 g and is just 2.5 cm long at the maximum. Once it grows to these measurements in 33 days, its mama gives birth to it.
Think of it as when a woman gives birth before nine months have passed. Usually, those newborns are not healthy enough to survive and are at a huge risk of death. So they are taken to a neonatal intensive care unit which resembles the womb in some way. There, the early-born babies are kept in warm boxes and provided with milk and nutrition for some time until they are strong enough to leave the unit.
Well, the exact same thing happens with the kangaroo. The joey is born incredibly early and is extremely underdeveloped. So it moves to its mother’s natural neonatal intensive care unit, the pouch. There, the joey continues its development until it is completely developed and ready to leave the pouch.
Is that not insanely wonderful? Now let’s look into the mechanism of how this happens.
Well, it happens in the most spectacular way because this 2.5-cm long, underdeveloped joey knows exactly where to go. However, it is assisted by the little development it received during the first 33 days of pregnancy.
When the joey is born, it already has some kind of a shape, with the four limbs roughly defined. At this stage, the forelimbs are usually more developed than the hind limbs. So the joey uses them, the forelimbs, to crawl up on its mother’s thick fur until it reaches the pouch.
This journey takes between three to five minutes. Once the joey reaches the pouch, it either crawls in or, which is how I like to think of it, drops itself, headfirst, inside the pouch. This is when a brand new and long chapter of development starts.
Just like a neonatal intensive care unit, the kangaroo’s pouch is equipped with everything the joey needs in order to survive and develop. From the outside, the pouch is covered with the kangaroo’s heavy brown fur. But from the inside, it is entirely hairless, just mere skin.
This mere skin is also very soft and tender. It keeps the pouch quite warm as well, typically at 32°, to protect the joey and help it develop.
The inside of the pouch has sweat glands that help release excess liquid, which might have microbes. In the pouch, there are also four nipples. They provide the joey with highly nutritious milk necessary for the joey’s growth and development.
Interestingly, the joey goes through different accumulative stages of growth during that period it stays inside the pouch. According to every stage, the components of the milk change to enable that growth. There is milk for the development of organs, another for the bones, and a third type for the fur. All of that is available through the four nipples found in the pouch.
The pouch is also supported by muscles which the mama kangaroo uses to open and close the pouch. So yes, it is not always open. Besides, the pouch expands to fit the growing joey, just like a woman’s womb enlarges during pregnancy or even like our stomachs, which get bigger when we have a heavy meal.
The joey stays in the pouch feeding for about four and a maximum of five months. This is when it gets more developed, furred, and open-eyed. Right at this stage, the joey starts pushing its head out of the pouch to explore the area around it. Since the kangaroo’s pouch is facing up, the joey usually looks at the world from the same perspective as its mother.
It pops up, takes a look and then goes back in.
This initial exploration lasts for a few weeks, during which the joey continues to develop not only physically but also emotionally. At around six and a half months in the pouch, the joey finally has the guts to leave the pouch and explore its surroundings more closely.
When the joey first leaves the pouch, it stays closer to its mama. Gradually, it starts going further and further. However, it eventually goes back to the pouch for a nap or a snack. By the way, the joey continues nursing during this period.
Every time it gets out, and further away, the now-little kangaroo feels safer. This encourages it to spend more time outside the pouch. After a total of eight months inside, the joey leaves the pouch permanently and starts to eat solid food.
Interestingly, a female kangaroo can mate right after the joey reaches the pouch. After 33 days, the newly fertilised egg grows into another joey. Although there are four nipples in the pouch, only one joey is permitted to grow there. That is why the mama kangaroo stops the second joey from getting born for eight months until the first joey is out of the pouch.
Another occasion when the female kangaroo suppresses the birth of a joey is when the surrounding conditions are not good for raising a child, if the food is scarce or when there is not enough water. So she stops the joey from getting to the pouch until the conditions improve. She would not risk losing her baby.
Here we come to the end of the second journey, where we explored another two amazing organs, the elephant’s strong trunk and the kangaroo’s mighty pouch.
In this article, we learned some hopefully interesting information about the elephant’s trunk. We explored some theories that explain its evolution, studied its composition and anatomy and learned how it performs a whole set of vital functions that help the elephant survive in its natural habitat.
Then we moved to the kangaroo’s pouch, which works as a second womb for the kangaroo baby to grow and fully develop. We discussed the kangaroo’s reproduction cycle, which explained the purpose and the role of the pouch. Then we learned how well-equipped the pouch is to allow the growth of a tiny foetus into a developed, fully furred kangaroo.
We hope you enjoyed reading this article as much as we loved writing it for you. If you have not yet read part one of this article series, you can find it here. You may also want to check this article if you want to learn more about kangaroos. Or you can read how the four seasons happen on Earth while you wait for part 3 to come out.
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