北极熊为什么要绝种 英语

北极熊为什么要绝种 英语
北极熊为什么要绝种 英语

北极熊为什么要绝种 英语
Why polar bears are going to be extinct?

Why are polar bears becoming extinct?
The polar bear is not listed with a status of endangered now, this may be due in part to the foresight of the five nations that agreed to make the polar bear ...

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Why are polar bears becoming extinct?
The polar bear is not listed with a status of endangered now, this may be due in part to the foresight of the five nations that agreed to make the polar bear a priority, and protect them by signing the International Agreement on the Conservation of Polar Bears. They are currently listed as "Threatened" by the US Fish and Wildlife Services, Endangered Species List, and the IUCN Red List, has them listed with a status of "Vulnerable" and the "population trend of decreasing".
The polar bear has suffered from various forms of hunting including, but not limited to, unregulated sport hunting from aircraft, and icebreakers, which were considered a common hunting practice at one time. Also, hunting polars bears in known "denning areas", during the birthing season. Many of these things are now prohibited, or regulated in the nations that are the polar bears range. But the polar bear is a slow reproducer.
Plus the very nature of the polar bear makes it difficult to protect. They do not behave as many other large carnivores, claiming large hunting areas that they then mark, and patrol. They are a free ranging species, even using many migrating patterns from hunting ice floes to the shore line and on inland. This makes the preservation of their habitat especially critical. Since they move over great distances following the ice floes for access to their main food sources, and denning areas, also this migration is controlled to some degree by the weather, breeding, and birthing seasons. The habitat loss is in large part a climate change driven issue alone, even though pollution has impacted polar bears habitat. It's also had a huge impact on them due to their specialized diet. They are the top predator of their region, so this exposure has been more along the lines of toxins through their food sources.
The polar bears are a specialized species, adapted to a specific environment, any change has a dramatic effect on the populations as a whole. Many studies are underway to try and determine what impact a major shift in the temperatures may have on this species. It is already known that females will not give birth if they themselves are already under weight, and if they do, often the cub is undernourished and the mother has trouble providing the cub with the proper amounts or quality of milk. The survival rate for cubs is on average low, but with any additional stress on the mother or cub, those rates will only decline further. The ability to feed the cubs will depend on her body being in peak condition.
Many scientists are uncertain as to what type of changes the polar bears habitat may experience, but they are agreed that even minor changes in the polar bears habitat will have far reaching effects on the polar bears populations, food sources, and on the stability of the ice floes.

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