In Australia, wild goats are eating grass everywhere, causing serious damage to the local ecology and causing headaches for the government.
wild goat
The ancestors of this group of wild goats were the ones brought by the British after they landed in Australia.
Some people are curious, since a few goats can grow to the scale of millions today, if 10 rams and ewes are placed on an isolated island, what will the scale look like in 10 years?
number of ideal cases
In this regard, you might as well make a bold guess on the number of ideal situations, provided that these 20 sheep are in a state of sexual maturity, and they are still in their prime, and these 20 sheep are all wild goats.
“Goat Experiment”
The sexual maturity of both rams and ewes is between 5 and 7 months. Depending on the breed, the number of litters per litter is between 1 and 3. Considering the survival of lambs, it is tentatively defined as one litter with two litters. son.
The gestation period of female goats is about half a year, which means that the number of goats on the island can reach more than 40 in the first year.
By analogy, if the area of this isolated island is not large enough, it is very likely that it will be filled with a large number of sheep in 10 years.
The reproductive capacity of goats should not be underestimated
The vegetation on the isolated island has been greatly reduced. When the food is lacking, the goats will even eat the bark. In 10 years, the isolated island may become bare, and a large number of goats will starve to death due to the lack of food.
Of course, this is the most ideal situation, without taking into account the constraints of various factors.
In fact, the reproduction of the flock is really not that simple.
goat huddled
no natural enemies
In the absence of natural predators, can wild goats really grow indefinitely? The answer is no, there is a vivid example in Yellowstone Park in Russia.
There is a kind of deer in the park. Since it is a protected area, there are no large carnivores in it. The life of this group of deer is very comfortable, and the number of deer has quickly increased.
After a period of time, the staff responsible for observing the data found something strange.
Logically speaking, the number of deer should increase continuously, but in the statistics of this staff member, the number of deer has reached a stable state.
deer herd
After a while, the number of deer actually showed a trend of decline, which surprised the staff and hurried to contact the local biologist.
According to the survey, biologists have found that there is a phenomenon of “aging” in the deer herd.
The increase in the number of old deer in the deer herd is constantly vying with the young deer for food, preventing the continued growth of the deer herd.
The reason is that there is no natural enemy to eliminate the old, weak, sick and disabled in the deer herd.
So why did the wild goats in Australia have no natural predators, and there was no such situation before the flood? In fact, it is also related to the local environmental affordability.
Australia has a vast terrain and rich products. The number of goats that can accommodate more than a few million goats must be more than a few million. Therefore, the environment in Australia has not yet reached the situation where old goats and young goats compete for food.
However, the resources of Yellowstone Park are limited. When the deer herd grows beyond the bearing capacity of the environment, the phenomenon of “containment” within the group will naturally appear.
It can be seen that the actual situation is not exactly what human conjectures, and nature has its own “uncertainties” in it.
inbreeding DNA
Inbreeding has long been a big problem for animals in nature.
British royal close relatives combine genetic haemophilia
The cost of human inbreeding is extremely high, but human beings are conscious to prevent mating between close relatives. Animals in nature are different. Compared with human beings, their cost is not high, and it will only be obvious after a few generations.
In addition, animals in nature do not consciously prevent the reproduction of close relatives, resulting in modern reproduction not surprising.
At this time, some people will ask, these 20 sheep are not related and not related, how can there be inbreeding?
While inbreeding won’t appear in the first 20 sheep, there’s no guarantee that it won’t happen in the next generation.
Sheep do not have the concept of monogamy, as long as the goat is in estrus, it is regarded as the object of mating.
For example, in the first year, male sheep No. 1 mates with female sheep No. 2, giving birth to male sheep No. 1.5, and in the second year, male sheep No. 3 mates with female sheep No. 2, and female sheep No. 2.5 is born.
In the third year, the 2.5 female sheep may mate with the 1.5 female sheep, and even the lambs after reaching sexual maturity will backcross with their elders.
Never underestimate the animals in nature. Animals have no concept of right and wrong. For the continuation of the species, they can do anything.
Reproduction is the first imperative for species survival
Male quolls choose to commit suicide for the survival of their offspring, and backcrosses between tigers also occur.
So how harmful is inbreeding to animals?
This kind of harm is not obvious in a short period of time, unlike humans, it will have a direct impact on the next generation.
Inbreeding in the animal kingdom is reflected in the genes of the next generation. Two close relatives cannot combine genes to promote species evolution.
Compared with other normal mating species, inbreeding has a slight genetic disadvantage, which is reflected in the ability to survive and adapt to the environment.
magic gene chain
The long-term close relationship between species is bound to lead to the decline of genes and the extinction of the entire population.
On a small island in Greenland, people have found a group of wolves. These wolves are closely related. This group of wolves has always been isolated from the outside world. In order to reproduce, they can only choose close relatives.
In the end, the bred pups have relationships that are more complex than humans can imagine.
After a period of time, it was found that the descendants of the descendants of the wolf packs had degraded their predation ability.
Lone Wolf in the Snow
After several generations of reproduction, the wolves eventually died out on the island, even though there were many animals on the island to feed them.
The fate of the wolves is likely to be the future of the sheep.
The same question, why are there no inbreeding of wild goats in Australia?
It is impossible to say that there is none at all, but in the early reproduction process, humans intervened.
At first, when the British brought goats, they kept them in the sheepfold. The British had perfect breeding technology and isolated the inbreeding of the sheep.
goat in captivity
When the British abandoned goat farming and drove them into the wild, the herd of goats had an instinct not to inbreed in their DNA.
In this way, after a few generations, the instinct in the genes faded, and there was a phenomenon of inbreeding, but at this time the flock had begun to take shape, and it was no longer important to be close relatives.
intra-herd competition
Of course, among these 20 sheep, there is also a very small probability that there is no close relatives. Each sheep abides by its duty and keeps the number of sheep growing.
When the flock exceeds the pressure of the island environment, internal competition between flocks begins.
In order to compete for food, some sheep had to evolve a larger body size to expand their competitiveness, and the genetic structure of these sheep that evolved a large body size has begun to change.
The next generation of sheep bred with it will also appear larger than the average sheep. With the passage of time, the size of the sheep population on the entire island will become larger.
As long as one sheep is “invoked”, it is only a matter of time before the “level” of sheep on the entire island is improved.
free lamb
Since it is possible for genes to change for the good, it is entirely possible for the genes to change for the bad.
Like God rolling dice, it is entirely possible that this randomness will lead to the demise of a species.
At the time of human evolutionary selection, from upright walking to intelligent creatures, every step of evolution was cautious, and maybe a little change would cause humans to favor another species.
Human beings are lucky to be born on earth and can be called the “highest masterpiece” of nature.
Humans are constantly evolving
In terms of results, placing these 20 sheep on the island will most likely not change much after 10 years.
If the time is put back to 30 years and 100 years, the result is definitely unexpected.
