How have polar bears survived so far with less ice? - Abby
Polar bears are having a difficult time living in a world with less and less ice. They need ice to hunt for seals, to rest and nurse their young and to breed.
They are not able to catch seals, their preferred prey, in the open water. They are not fast enough. On the ice they wait, sometimes for days for a seal to poke it's head up through a breathing hole in the ice. Then they pounce on the unsuspecting seal and have a meal.
It takes a lot of energy for polar bears to swim through the arctic waters and they get tired, especially the young ones which often can be seen riding on their mothers backs. As the distance between ice floes increases, there are less resting places. Researchers are finding more and more polar bears that have drowned because the distance was too great. One mother polar bear swam for nine days straight, covering a distance of 426 miles. Scientists tracked her because she was wearing a collar. She lost 22% of her body weight and her cub.
When polar bears are out on the arctic ice during the winter, they need to be able to find each other during breeding season. Polar bears have a very good sense of smell and can find each other from miles away if they stay on the ice. The female leaves a scent trail as she wanders across the ice. But if the ice is broken up with large areas of open water between ice floes, the trail is lost. The loss of ice will limit the number of baby polar bears born each year.
That was a great question Abby. The answer is not simple - it is actually quite complicated.
How many seals do polar bears catch in a week? - Kenny
A polar bear needs to successfully catch 2 seals every 7-10 days to maintain a healthy weight.
Good question Kenny! Did you know a polar bear can eat 100 lbs. of blubber in one meal - WOW!
How long does it take for a polar bear to kill a narwhal? -Rachel
Narwhals are not easy prey for polar bears to catch, Rachel. When they are free swimming in the arctic ocean, the bears can't catch them at all.
However sometimes narwhals and whales get trapped in a small open water opening in the pack ice. When this happens, often a group of bears will wait on the surrounding ice for the animals to surface, and then they pounce. It doesn't take long for them to kill a trapped narwhal.
Narwhals can weigh 2650 lbs. and can provide a much needed meal for several polar bears for many days. Excellent question!
How long can polar bears stay underwater? -Sophie
Polar bears can't stay under the water very long since they need to come up to breath just like you and I. There have been documented events where polar bears dive down deep into the arctic waters to bring up the remains of a whale carcass.
If you watch the polar bears at the Detroit Zoo, they frequently will stay underwater for longer than a minute as they play or pick up food tossed into their pool by the zookeepers.
The longest a polar bear in the wild has been timed holding it's breath while diving is 72 seconds - a little over a minute!
Interesting question, Sophie!
How large can a polar bear get? -- Olivia
WOW - this is a HUGE question Olivia!
Adult males measure 6.5 to 12 feet tall and normally weigh 775 to 1,200 pounds. Adult females measure 6 to 9 feet tall and normally weigh 330 to 650 pounds. The largest polar bear ever recorded was a male weighing 2,209 pounds.
How do polar bears sleep? -Reis
This is a really interesting question, Reis!
Most polar bears sleep for seven to eight hours at a stretch and they take naps, too. In that way, they’re a lot like people.
On the ice in spring and summer, polar bears tend to sleep more during the day than at night, probably because seals are more active at night. But day and night hold little meaning in the Arctic where there are 24 hours of daylight in summer and 24 hours of darkness in winter.
The cubs grow rapidly, thanks to the calories in their mother's rich milk, which is about 31% fat. In March or April they emerge from their den. It takes a few days for the cubs to adapt to the arctic temperatures but within a short time they are out on the sea ice with their mom, hunting seals, never to return to their maternity den.
Where do polar bears sleep? -Carson
In winter, polar bears sleep in shallow pits they dig in the snow with their sides or backs to the wind.
Polar bears sleep right through blizzards in day beds dug in the lee of a ridge. The snow piles up on top of them and provides an insulating blanket. Sometimes they stay curled up under the snow for several days until the storm passes.
In summer, polar bears curl up on the tundra or on an ice patch, sometimes using a block of ice or an outstretched paw as a pillow. Landlocked bears dig sleeping pits in the sand or in gravel ridges along the shoreline.
Pregnant females dig maternity dens in snow banks in fall and give birth to cubs in early winter. Until March or April when they emerge from the den, mother and cubs spend their time sleeping.
Go Carson - good question!
How many Pizzlies have been found? - Isiac
There has been only one Pizzly found in the wild. It was shot by a hunter in who thought he was shooting a polar bear in 2006. A Pizzly or Grolar is half polar bear and half grizzly bear. This has occurred in zoos before but has never been seen in the wild.
The Pizzly is not well adapted to either the arctic or the woodland environment of the grizzly so could have a much harder time surviving in the wild. Some scientists think that as the ice melts and grizzlies are able to move north into the territory of the polar bear that these encounters between the two speies may happen more often.
Great question, Isiac!
Do the polar bears have any predators? - Evan
Humans, and on rare occasions, other polar bears are the only predators of polar bears. The hunting of polar bears by humans is tightly regulated now as they are a threatened species. Most of the hunting is done by the native Inuit population. Called sustainable hunting, villagers take only the number of bears they need to live on for the year.
Great question, Evan!
How many babies might a polar bear have over the course of her life? -Josh
Twins are most common, but they can bear singlets or triplets depending on their condition. They give birth to their first litter when they are between four and eight years old—most frequently at five or six. Polar bears have one of the slowest reproductive rates of any mammal, typically producing only five litters in their lifetime.
Great question, Josh!
Do polar bears eat other bears? -Nick B.
Some scientists believe that food stress is increasing acts of cannibalism, which has historically been a natural, but infrequent event. It seems that as the ice melts, there are more and more reported attacks of large male polar bears on young polar bears.
Good question, Nick!
- Posted using BlogPress from my iPad.
No comments:
Post a Comment