They do it because polar bears are rare and are being hunted by poachers.
because they have people to take care of them
Yes and No because some captivity is for research and isn't harmful.Smuggling captivity can kill polar bears in less then a day
Andean bears (Spectacled bears): 30 to 35 years for females and 36 to 40 for males in captivity
ther are some polar bears in zoos, but the majority live in the north of /Canada and Russia
grizzly bears usually live for about 40 years in captivity
In the winter
The heat in their summer months.
That means they are bored and don't have enough room.
Bears HAVE instinct much like people have instinct. So take that as a Yes or No. Or if you mean "are bears EXTINCT" then No. Instinct and extinct are not opposites.
In captivity, polar bears live to their mid to late 30's. In the wild they live an average of 15 to 18-years. Scientists have tagged a few polar bears in the wild that have lived to be in their early 30's.
Polar bears are expected to live for as long as 30 years in the wild while in captivity they can live for 40 years.
This depends greatly on the species. Generally animals live much longer in captivity. While some bears can reach the mid-thirties there have been recorded cases of bears living up into their forties.