【Native Speaker每日综合训练—45系列】【45-03】科技 Polar Bear

carrieli0805

感谢@古月小破烂 @Going
time2: 2:30
the population of polar bear has been declining since 2001. there are some unstudied groups because they live in remoteness area. From the studied group, there are five decreasing, four stable, and only one surprisingly increase. However, the overall in number declined. Location is most important factor to this variability. because of the globe warming, the ice pack is melting and become thinner.
time 3: 2:50
the ice pack is a platform for polar bears to prey, and the melting speed is far faster than what the scientists imagined.  Because of lack of solid place on the ocean, the bears start to find some food on land, but those plants are not enough for them to sustain their energy. they still need a plenty of fat fish. A forecast shows that the population of polar bear will be one third of current number in 2050
time 4: 2:30
can polar bear survive on the land? scientist said that the bear can live on land for less then 6 month and eat some goose eggs or geese. they are standing in the melting icing to find seals. In the past, they used to live on land only for snooze or keep their energy, but now because of the climate change, they have to live on land more than 6 month during the ice free period.
time 5: 3:50
if the free ice time is more than 6 month, how can bear survive? one scientist said that they can find a lot of food on land such as the goose eggs, geese or caribous. But the question is whether the energy that the bear get from those preys is more than that they spend on chasing them since the adult and productive bears' consuming amount will be larger than younger. However, another scientist said that the real problem is not about the energy, it is whether the bears will still strong enough at that time, since lack of sea food bears are becoming weak.
time 6: 3:12
some genes are different between polar bears and black or brown bears. The polar bears' gene included some oxide that can help them to keep warm without eating and spend less energy to transfer to heat.