The zoo has two pairs of eagle owls, the breeding rate of eagle owls is very high, the annual production of two litters, a year later reached twenty-six, but six years have passed, two pairs of eagle owl only developed into four pairs of eagle owl, plus two old and dead eagle owl, six eagle crows in six years, an average increase of less than one a year. After the zoo found the reason, it took measures.
Many animals are so fertile that rice leafhoppers are born five to seven generations a year and can swell into a group army after a year.
Domestic rats produce three to four generations a year, and after three months, the young rats grow up to mature and can give birth to cubs, and a pair of house rats becomes more than two thousand after one year.
The lower the animal, the higher the reproduction rate; the higher animal reproduction rate is lower. For example, in elephants, females give birth to an average of five or six years, and each litter only gives birth to one cub.
Nature adheres to the principle of survival of the fittest, and animals at the bottom of the food chain are attacked by predators, and diseases and natural disasters threaten their survival, and if fertility is delayed, this species will be eliminated by nature.
If rats only give birth to one litter in five or six years, and each litter only gives birth to one cub, it will be caught and eaten by predatory beasts such as jackals and wolves.
High reproduction against high attrition is a survival strategy adopted by animals.
The zoo has two pairs of eagle owls, half a meter long, fierce and powerful.
Owls predominantly eat rodents. An owl destroys 500 mice a year, the eagle crow has a higher ability to catch rats, and a eagle owl destroys an average of 1,000 mice.
The reproductive rate of eagle owl is high among carnivorous birds of prey, producing two litters per year, each litter of twelve eggs, reaching twenty-six after one year, and the young birds will lay eggs and hold nests after one year of maturity, and in less than three years, the cage will be stuffed with eagle owl!
Six years have passed, two pairs of eagle owl have only developed into four pairs of eagle owl, plus two old and dead eagle owl, six eagle crows have been added in six years, and the average increase of one in a year is less than one.
Some animals leave their homeland, are depressed, and will stop breeding.
"Eagle owl are highly adaptable birds that lay eggs and nest in cages just like they do in the wild." Ornithologist Professor Wu said.
"Why is the reproduction rate of eagle owl so low?" I asked.
"Eagle owls regulate fertility based on the number of rats, and the zoo only feeds the eagle owl mice once a week, and they keep their fertility to a minimum."
There are not so many live mice in the zoo to feed the eagle owl every day, usually put shredded pork, only on weekends to feed the mice, each eagle owl to supply two mice. As a result, during the spawning season, a female eagle owl lays only one or two eggs.
It is humbling that the little eagle owl is so sensible about fertility.
Eagle owl lay the most eggs in years when rodents are rampant, with more than ten eggs per nest, and if the rodents decrease, the eagle owl will adjust the number of eggs laid, sometimes even to only one egg per nest.
Rats give birth blindly and reproduce at a high rate to ensure prosperity. Eagle owls come and go according to the amount of food, regulate fertility, and are conducive to the survival and development of the race.
Rat rampant years, abundant food, more offspring, if the rodents are reduced, food is scarce, and as in the past, a large number of birds are born, and only three chicks can feed the food to feed more than a dozen chicks, in the process of food competition, most of the chicks die of cannibalism or starvation.
The wisest thing to do would be to reduce the number of offspring to match the number of fed rodents.
Many highly intelligent animals regulate fertility according to changes in the environment, climate and food resources.
A group of wild elephants living in a nature reserve, twenty years ago, was seventeen, and the protected area was burned by villagers to open up the land, and the forest area is constantly shrinking.
Wild elephants have not given birth for twenty years, and seventeen elephants have been sharply reduced to twelve, all of which are middle-aged and elderly elephants. Five years ago, the government stepped up efforts to return farmland to afforestation to improve the living environment of elephants, and two milk elephants appeared in wild elephants, ending a twenty-year history of infertility.
There are also animals that can control the number of their offspring, but with cruel means.
In the year of drought, the African lion herd is depleted of water and food, and the lioness will eat the newborn lion cubs, reduce competitors, and survive the famine year.
When I was a young man, there was a pair of woodpeckers living in the banyan trees in the yard, and six to eight chicks were bred every year, but one year in March, frost fell, many tree species froze to death, and the food moths of woodpeckers were sharply reduced.
In late spring and early summer, woodpeckers hatch eight chicks, eight chicks waiting to be fed, and two parent birds cannot satisfy the chicks.
On this day I heard the screams of chicks coming from the big banyan tree, and a parent bird stood on a horizontal branch with a bug in its mouth, and the chicks wanted to eat the bug, but the parent bird shook the bug above the chick's head.
The chicks huddled to the edge of the nest and shoved each other, and one thin chick was squeezed out of the nest by the other chicks and fell off the tree.
The parent bird turned a blind eye and shook the bug as usual. Six fell from the nest from the nest and died. The parent bird stuffs the bug into the mouth of a chick and ends the game of death.
This pair of woodpeckers are regulating their fertility according to food, but they are not predicting the number of eggs laid in advance, but they are regulated afterwards by means of survival of the good and the bad, reducing the number of offspring.
In the past two years, the suburban rat population has swelled, and the grain of many farmlands has been wasted by rats.
The government requires zoos to breed more eagle owl and place them in areas where rat infestation is rampant. Employees feed four pairs of eagle owls to mice every day.
It is the spawning period of eagle owl, each nest has eleven or two eggs, and after three months more than forty chicks hatch, and after half a year, these grown eagle owl are released into the field, which plays a role in curbing rat infestation.
Life's instinct is to keep copying genes to leave offspring. The development of any species is constrained by conditions such as geography.
Unrestricted development has disastrous consequences, a species that reproduces more than the density will break the ecological balance, causing intra-group fighting until a new equilibrium has come to an end.
An average of fifty square kilometers of mountain forest can support a tiger, if there are ten tigers, the herbivores will be consumed, ten tigers will fight for the right to survive, and nine of them will either flee elsewhere to open up territory or be killed.
Eagle owl is a model of family planning.
The story is adapted from "Owls of Family Planning", the author Shen Shixi, this article and pictures from the network, the copyright belongs to the original author, if there is infringement, please contact me in time to delete, thank you!
Ring ring wants to say,
Animals are very rational, giving birth to children according to the amount of food, and living within their means. When the conditions improve and food is abundant, the animals will multiply in large numbers and be shrewd.
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