For organisms that reproductive in both sexes, mating is crucial, but different organisms have very different mating methods. Amphibians represented by frogs usually use in vitro fertilization. Female lays eggs on the water surface, and then males also excrete germ cells here to fertilize the eggs. However, the disadvantage of this method is that the probability of fertilization is low and the external environment is unsafe, resulting in a low survival rate of offspring. Therefore, amphibians usually discharges a lot of eggs.
But mammals are different. Most female mammals can only discharge a limited number of eggs at a time. In order to ensure the offspring as much as possible, mammals usually conceive by in vivo fertilization.
Different animals have different mating time. Among them, the longest mating time is the Australian marsupial creature bag shrew . They can mating for up to 14 hours, but they will die immediately after mating; the shortest mating creature is a giraffe, which has only 1 second mating time, and they will do a lot of preparation before mating.
Bag shrew
We know that Australia is surrounded by the sea, and many terrestrial creatures cannot travel through the vast ocean to come here, so the creatures here have almost no communication with other continents. Over time, they have formed local marsupial creatures, such as: kangaroo , wombat , thyrol , treacherous lion and treacherous shrew.
bag shrews look very much like little mice, but their noses are different from those of little mice. Like other marsupial creatures, the bag shrew has an parenting bag . When the offspring is born, they can hide in the parenting bag and continue to develop. But what makes bag shrews different from other creatures is that whenever the males in the estrus period, they will not eat or drink, and will only think about mating.
The reason for this phenomenon is that is because there is an excessive amount of testosterone in the gene of male pouch shrews, which is a kind of androgen. During the estrus, this gene will prompt them to mating wildly.
However, excessive testosterone also causes them to live very short. Usually, they will frantically search for the opposite sex during the mating period. Once found, they will mate for a long time, up to 14 hours. However, during mating, excessive testosterone can also cause male pouch shrews to fall off, their eyes gradually become blind, and their whole body will die of bleeding. Because of this characteristic, male pouch shrews rarely survive until the next year, while females survive for several years.
We know that during the evolution of organisms, the characteristics that are beneficial to the survival or reproduction of organisms will be selected by natural selection. So what are the benefits of male pouch shrews for population survival?
In fact, the death of male pouch shrews can increase the survival rate of offspring. We know that the competition among organisms in the wild is very fierce, and there may be many biological species competing in the same ecological niche, such as: cows eat grass, and sheep eat grass. Cattle and sheep are the relationship between food competition.
Not only will there be food competition between different organisms, but there is also food competition between the two genders between the same race. When the male pouch shrew dies, it can save some energy, so that the female will have a higher success rate foraging and the higher the survival rate of offspring.
When the next breeding season comes, the little male pouch shrew born in the previous year has reached the sexual maturity stage and can continue to continue the estrus mechanism of ancestors.
Giraffe
The difference between a bag shrew is that male giraffes can live for many years and their lifespan is almost the same as that of females.
The mating time of giraffes is very short, only about 1 second. Although the mating time is short, they do not have much preparation before mating.
First of all, male giraffes also ride on their own, but most of them occur between the same sex.Cross-ride between homosexuals is also common among other animals, but other animals generally have the ability to determine status, while giraffes are not for determining status. According to scientists' observations, even if the giraffe rides on another body, the other giraffe will not surrender to the giraffe.
Scientists speculate that the reason they ride across the board may be to do exercises for real mating.
And During the estrus period, whenever the female releases a estrus signal, the male will follow the other in a row, but they are not in a hurry to mate, but will "taste" urine first. The giraffe’s upper lip can distinguish the chemical composition in female urine, and they will only mate with females when they analyze from their urine that the female is in estrus.
Female giraffes are very timid, and it is generally difficult for males to succeed, but once they succeed, they can end mating in just 1 second. This is because the environment in which giraffes live is very dangerous and mating is a period of very fragility. If they are mating for too long, they may be captured by other animals.
Summary
Whether it is the long mating time or the short mating time, they are essentially for reproduction. However, because different organisms live in different environments and face different survival pressures, their behavioral habits are also different. It is precisely because of this that nature presents such a rich and colorful biological population.
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