This paper takes part in the series essay competition of “great science” of Recordunkown
In China, the panda is a lovely national treasure; in Australia, the national treasure is a lovely kangaroo. In this sparsely populated country, there are groups of kangaroos. According to incomplete statistics, the number of kangaroos in Australia is about 60 million. It can be said that kangaroos are unique to Australia, and they are also the highest and farthest jumping species among mammals. In addition, whether it is female kangaroo, or male kangaroo, their reproductive capacity is different, has a super reproductive advantage.
Kangaroo is the earliest typical representative of mammals. Relevant scientists speculated that kangaroo had been widely distributed on the earth in the Cretaceous. However, most of the kangaroos will die under fierce competitors, and finally go into recession or extinction. Only Australia’s kangaroos are isolated from the world, and the vast territory and sparse population make them the best refuge. Kangaroo’s front legs are relatively short, and its hind legs are particularly strong. It runs with a jump belt. Its long tail is responsible for controlling kangaroo’s sense of balance when jumping. Without the help of its tail, kangaroo will not jump steadily and high at all. Sometimes, when kangaroo is resting, its tail also plays a supporting role, which is a “good chair” for kangaroo to support its body.
Kangaroo mating time is long, female kangaroo will be “barbaric” action and die
Animal’s “sexual behavior” is inborn, it is a kind of instinct, in the process of mating, different animals will have different strange performance, such as barnacles, their genitals are dozens of times of their own body length. Wild animals have their own mating rules. For example, male walruses can mate with multiple female partners, and East African female lions can mate with multiple male lions. The animal kingdom mates in a variety of ways, and they do so in order to survive and produce more offspring. It is worth mentioning that the mating process of kangaroo is quite special. If the male kangaroo uses too much force, the female kangaroo will die accidentally during mating.
When the male kangaroo is in estrus, they tend to keep close to the female kangaroo and take the initiative to pursue courteous. When the oestrus is out of control, the male kangaroo will reach a crazy state. They will constantly tease the female kangaroo and sniff the back and genitalia of the female kangaroo. We can also understand the behavior of the male kangaroo as “SEDUCTION”. Under the constant temptation, the male kangaroo will successfully attract the attention of the female kangaroo and grasp the physiological changes of the female kangaroo. In the repeated seduction of “play hard to get”, the female kangaroo will throw herself into the arms, while the male kangaroo will succeed in courtship.
However, it is worth mentioning that female kangaroos are more reserved animals. At the beginning, they will resist the “obscene” behavior of male kangaroos, and even choose to run away, while male kangaroos will not give up and chase them. After the two creatures stop and run, the female kangaroo has to compromise with the male kangaroo, so the two similar creatures directly enter the mating link.
The whole mating process is about half an hour. During mating, the male kangaroo chooses the “back in” style. The first round of intermittent mating takes only a few minutes. However, the second mating process takes a long time, and multiple mating can improve the pregnancy rate of female kangaroo. If the female kangaroo is very resistant, the male kangaroo will choose barbaric “rape”, excessive mating behavior will even make the female kangaroo die unexpectedly. The female kangaroos who choose to give in, after the male kangaroo completes mating, they will enter the “excited mode”, constantly sniffing the male kangaroo’s genitals, to tease each other.
The male kangaroo’s genitalia is “Y”
The female kangaroo has three vaginas and two uterus
The biggest difference between male kangaroo and other male animals is that the penis of male kangaroo is in the shape of “Y”, that is, in a long penis, there will be a midway bifurcation, and the two bifurcated channels will transport sperm. The vagina of female kangaroo has three channels, two of which are responsible for the introduction of sperm into the uterus, and the other channel is responsible for the birth of cubs. The three vaginas converge into the cloaca and open outside the body (cloaca is a relatively primitive structure, which is the common outlet of intestinal tract, urethra and genital tract). Some netizens can not help but ask: “kangaroo’s two wombs, what role does it play?”
It can be said that the female kangaroo can achieve co breeding. The uterus on the left is just responsible for giving birth to the baby. A few days after the baby is born, the uterus on the right will soon have a second baby. For example, it’s like a long track, with track branches in the middle. Different trains can send passengers to different destinations. As soon as this wave of passengers arrive at the destination, another wave of passengers will get on the train again and go to another destination. The function of the train is to transport different passengers to different destinations. Similarly, for a female kangaroo, its womb gives birth to cubs all the year round, which is why its reproductive rate is so high. One cub is in the pouch, while the other is in the womb. This is the magic of a female kangaroo.
It is worth mentioning that the kangaroo mother’s pouch will hold the baby kangaroo for more than 200 days. During this period, all the eating, drinking and scattering processes of the baby kangaroo will be completed in the pouch. The mother kangaroo will also clean up the excrement in the pouch every day and lick it clean to help the baby create a comfortable environment. Sometimes, when the little kangaroo sticks out her head, the mother kangaroo will press it down. The little kangaroo is more and more naughty, and its head is pressed down. After a while, it will stretch out its legs and sometimes drag its tail outside the mouth of the kangaroo. From mating to giving birth, the whole process is very hard for female kangaroos. Sometimes they have to not only take care of the baby in the pouch, but also “pacify” the “fetus” in the womb.
Can male kangaroos mate twice at the same time? What’s the use?
For the male kangaroo, their Y-shaped genitalia, played a “two pronged” role, can improve the fertilization rate and reproduction rate, this kind of multiplier effect, is no mammal can achieve. Male kangaroo mating once can play the role of twice, and the two wombs of female kangaroo will be pregnant in turn.
Earlier, we have mentioned that the mating mode of kangaroo is “backward entry”, that is to say, the Y-shaped genitals of male kangaroo can just enter the two vaginas of female kangaroo, and play the role of mating twice at the same time. From this point of view, the breeding rate of kangaroo is also the highest among mammals. This is just like the washing machine used in our daily life, it also plays the role of drying while washing clothes, and the two pronged task can be completed at the same time.
From the mating strategy of kangaroo, most of the male kangaroo will accurately grasp the mating opportunity, take the “play hard to get” way, let the female kangaroo completely submit to themselves, do not give them any chance to resist, backward mating way, can let the male kangaroo will be strong sperm all transported to the womb of the female kangaroo, better reproduction.
The special genital structure of male and female kangaroos has brought troubles to the Australian people
Although the male kangaroo’s Y-shaped penis and the female kangaroo’s three vaginas and two uteruses can help them to reproduce better and improve their survival rate, it is very distressing for the residents living in Australia. Although kangaroo is Australia’s national treasure, but also the lowest status of national treasure. The number of kangaroos in Australia has been growing. On the surface, kangaroos are very docile mammals, but they are very tough and like to challenge the bottom line of human beings. For example, they often run to the bustling city, and even rush into the road. Their sharp claws are very easy to scratch human skin. In Australia, the news that ordinary residents are attacked by kangaroos is not uncommon.
“These guys are so bad. Sometimes when you open the gate of the small courtyard the next morning, you will see them. The more you want to drive them away, the easier they will be kicked. Their legs are very powerful,” said a small town resident living in Australia “Don’t say that ordinary people are driving on the road, even the competitors will be intruded by kangaroos when they are racing. This kind of picture is really indescribable.”
This shows that the so-called “national treasure” kangaroo is already lawless in Australia. Due to the increasing number of kangaroos, the Australian government began to announce the shooting of kangaroos, which may be the most miserable animal in history. Because kangaroo meat has a strong fishy smell and a very bad taste, it has almost no market. Many businesses process kangaroo meat into cat food and dog food.
However, from a personal point of view, kangaroo’s special reproductive structure helps them to improve their reproductive rate, which is not their own fault, but their inherent basic functions. Every wild animal has the right to survive in this earth, and animals, like human beings, also have dignity and feelings. Although they can’t express their true feelings in language like human beings, they should have the same right of survival as human beings in the earth.
We should not only protect wild animals, but also respect and protect other companion animals, laboratory animals and endangered animals. We should not regard them as our private property, let alone abuse and abandon them. In particular, the survival right of wild animals, how to protect them from physical and mental harm, is worth thinking about. In this world, all things are equal. Although we are at the top of the food chain, we should also respect all life. Because any kind of animal has its existence value, is an indispensable part of the human ecosystem, we should treat them well.