Kangaroos are bizarre animals … Like almost all the creatures that populate this gigantic country, Australia. Did you know that this island, the size of a continent, is home to a whole bunch of deadly creatures? Even the ornithorynques are poisonous … Well, the kangaroos do not have dart or fangs filled with venom, but they are still able to put a human to the carpet. These animals are actually equipped with impressive muscles and in addition … they jump! Why don't they move like other mammals, walking?
You should know that there are three types of mammals: placental mammals, largely in the majority and of which we are a part, the monotrèmes and the marsupials. Among the monotrèmes, the little ones are born in eggs. This is the very example of the ornithorynque.
As for the marsupial, it is primitive mammals that have a ventral pocket. The latter contains the udders and welcomes the little ones after birth. Kangaroos are famous representatives of this category.
Marsupial animals are born after a very short period in utero. This can even correspond to only a few days in certain species, such as bandicoots. The newborn marsupials are therefore tiny, compared to the placentaires. They weigh less than 1 gram and are very little developed. We even speak of “marsupial larva”.
After birth, the little ones migrate in their mother's pocket, looking for the udders. The “larvae” then remain hung on these udders over a much longer duration than gestation. They will develop, up to the juvenile stage, relatively autonomous and similar to adults.
In kangaroos, gestation lasts only 30 to 40 days depending on the species. At birth, the “larva” is only 2 cm for barely 0.8 g. She joins her mother's pocket and will develop there for the next 9 – 10 months.
Kangaroos are marsupial mammals whose little ones develop mainly in their mother's pocket.
Credits: Shutterstock/Edwin Butter
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Kangaroos… who jump everywhere?
Kangaroos are not only original compared to their mode of reproduction. Their way of moving is also unique in the animal world …
These animals are designed to be jump champions, both in height, in length. Thus, in humans, the world record for high jump is 2.44 m and that of long jump of 8.90 m. However, the kangaroo can cross 3.30 m high and more than 9 m in length … impressive!
In reality, these performances are achieved when the animal feels in danger and flees. Usually it rarely jumps further than 1.90 m. A mode of travel that still allows you to move at more than 20 km/h.
The body of kangaroos is perfectly suited to this mode of locomotion. Their rear legs are very long and powerful and much more developed than the front legs. (It would remind a famous T-Rex…).
These impressive rear legs work in tandem. They propel the animal forward thanks to the muscles of the thighs and glutes, very numerous and developed. In addition, the long and elastic tendon acts as a spring. Each landing, it stores the energy produced during the shock with the ground. The latter is then used for the next leap.
This well thought out mechanism requires little energy from kangaroos. The storage and release of energy in the elastic tissues allows a lower expenditure of oxygen. In the end, the faster the kangaroos move, the greater the stored and reused energy and the less they get tired.
On the contrary, studies have noticed that when kangaroos move at less than 18 km/h, they spend more energy than an animal of the same 4 -legged current weight. What seems the most tiring for these animals is in particular the four -legged position, which they use to graze.
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But … why jump?
If kangaroos jump, it is not by choice. But out of necessity. It is evolution and adaptation to their environment that imposed this mode of movement.
Kangaroos belong to a family of particular marsupial mammals, macropodids. An idea of what that means? I give it to you in a thousand … “big feet”.
This family would have appeared between 12 and 30 million years, following various factors. It is true that scientists do not yet know exactly why the evolution has pushed the kangaroos jumped.
They expressed several hypotheses, ranging from the leak of predators, to the preservation of energy, passing by the arrival of an open environment, savannah type, in place of forests. This drier climate would then have favored individuals capable of moving quickly and effectively to the different water points.
So we don't know exactly why kangaroos jump, however, we know that they are really made for that. So much so that some trips are impossible for them. For example, they are unable to walk on their back legs. The latter cannot operate independently of each other.
Likewise, the muscular, bone and tissue composition of the rear legs does not allow you to jump … backwards. Kangaroos can only go forward (eternal optimists?).
Kangaroos are fascinating and unique animals. They still have a lot of secrets to reveal … which makes them even more intriguing!
>> Read also: This unique Australian marsupial is in danger, the deforestation in question
With an unwavering passion for local news, Christopher leads our editorial team with integrity and dedication. With over 20 years’ experience, he is the backbone of Wouldsayso, ensuring that we stay true to our mission to inform.
