Polar bears are only found in the Arctic. The most important habitats for polar bears are the edges of pack ice where currents and wind interact, forming a continually melting and refreezing matrix of ice patches and leads (open spaces in the ocean between sea ice). These are the areas of where polar bears can find the greatest number of seals. As the sea ice advances and retreats each season, individual polar bears may travel thousands of miles per year to find food. Polar bears are distributed throughout the Arctic region in 19 subpopulations, including Alaska, Canada, Russia, Greenland and Norway.
1) Unlike some other at-risk mammals (such as tigers and rhinos), hunting is not the biggest threat to polar bears right now. They used to be heavily hunted, from the 1600s right through to the mid-1970s, but then strict regulations were agreed internationally to protect the survival of the species.
2) The big threat to polar bears now is climate change. Global warming means sea ice is melting earlier and forming later each year, leaving polar bears less time to hunt. A recent study (published in Nature, Feb 2011) shows polar bear litters are also decreasing in size because of sea ice decline. Many scientists believe polar bears could be gone from most of their current range within 100 years.
3) The polar bear is officially classified as ‘vulnerable’ by the IUCN – although the US government recently listed it as “threatened” under its own slightly different classification system. There are 20-25,000 polar bears in 19 groups across the Arctic area, more than half in northern Canada.
4) Polar bears actually have black skins and colourless hair – but those thick, hollow hairs reflect light to give its white-looking coat. Great camouflage in the snow, as well as being very effective insulation.
5) Polar bears like to keep themselves clean – probably because it helps the insulating properties of their fur. After feeding they’ll usually wash by taking a swim or rolling in the snow. They also roll in the snow to cool off.
6) Polar bears do overheat, despite their harsh environment. They’re superbly adapted to resist Arctic temperatures (which can dip to -50C), but the disadvantage is the risk of overheating, especially when running, or in balmy above-freezing summer temperatures.
7) Polar bears are excellent swimmers – their Latin name means ‘sea bear’. They can comfortably swim at around 6mph, using their front paws like oars while their hind legs are held flat like a rudder.
8) They have a pretty good sense of smell too – they can detect seals, their main food, from almost 1km away.
9) When first born, a polar bear cub is about the weight of an adult guinea pig. A cub stays near its mother for about two years. By the time it’s fully grown it can weigh over 500kg.
10) Less than 2% of a polar bear’s hunts are successful – despite their reputation as fearsome hunters (they’re the most carnivorous of the bear family), they expend a lot of energy in the process. And all that time and energy spent finding food will only increase as Arctic sea ice disappears and their prey (mostly seals) become harder to find.
Scientists and Auroras
Scientists have spent many hours studying these lights, trying to understand how it came to be. One of the early theories was that the Northern lights are a reflection of the light from the ice caps. The first scientist who started seriously studying this phenomenon was Galileo Galilei who came up with the name aurora borealis borrowing names from Aurora, the Roman goddess of the dawn, and Boreas, Greek name for the northern wind.
Auroras on Other Planets
Because there are magnetic fields on other planets in the Solar System and deep atmosphere on Jupiter and Saturn, the gas giants, they have spectacular auroras. Mars also has auroras, although much weaker than on Earth.
Where to Go to See It?
The best places to view auroras are high northern latitudes during the winter, Alaska, Canada, and Scandinavia. During very large solar activity events, the aurora may be seen throughout the US and Europe, but these events are rare. The furthest it has been recorded was in Mexico City back in 1958.
Various debris, radiation, and other magnetic waves from space attack Earth daily. Without a shield, there would be no life on the Earth. Our planet’s magnetic field does a good job of protecting us and deflecting the deadly rays, including the ones from the Sun. When the particles approach the globe, they are drawn to the poles.
What Are the Northern Lights?
Solar wind or particles from the Sun rush towards the Earth at a tremendous speed of 90 miles per second on a journey of 93 million miles through space to tackle the Earth. When they enter the Earth’s atmosphere, they are mixed with oxygen and nitrogen gases and create light.