4.1
Unusual winter weather events cause rapid changes in the tundra

Did you know?
Unusual weather events happen in summer as well as winter. One village in Siberia experienced 38 degrees C in June 2020 (hotter than Italy) and warm periods above freezing in winter when it can rain on snow are becoming more frequent.
Unusual weather affects biodiversity very quickly.
A few warm days in winter, particularly with rain, can kill animals such as reindeer and lemmings which cannot access their food under the ice.
The dead animals attract scavengers from the south
Another extreme weather event that is increasing is the number of lightning strikes that cause forest fires and kill animals: 350 musk ox were killed in Norway by one lightning storm.

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When animals from different areas meet, one of two things can happen:
  • One displaces the other e.g. the red/grey squirrels in UK, Arctic/red fox in Scandinavia. We can predict the 'losers' – they are the very specialised animals. For example, what happens to the Arctic Fox when there is no snow? It will be unable to camouflage itself to hide from predators and also to hunt for prey, which increases its susceptibility to be hunted itself or starve.
  • They get on and cross breed
Pizzly Resource
When was the first pizzly-grolar discovered?
The first reported sighting – or more accurately, shooting – was in 2006. Since then, eight further sightings have been confirmed as polar-grizzly hybrids by DNA testing, with a ninth awaiting confirmation.
Where have they been seen?
All confirmed sightings have all been in the Canadian Arctic, but there is no reason why they couldn't exist in Russia or Alaska where the two types of bear are known to overlap.
What do they look like?
A little bit like mum, and a little bit like dad, with cream or light tan fur, the slender snout of the polar bear and broad shoulders of the grizzly.
Have they ever met before?
Yes. Studies show that polar bears and grizzly bears have occasionally met before. The two species first diverged between 479,000 and 343,000 years ago! But with the increasing likelihood of a large amount of sea ice disappearing relatively quickly due to climate change, scientists expect to see many more examples of the two species meeting.
Is one species more dominant than the other?
It looks like the grizzly bear DNA is more dominant. There are four known second-generation hybrids that are three quarter grizzly and quarter polar bear. This is bad news for polar bears as the unique genetic traits that allow them to survive in the harsh conditions of the Arctic and live on the sea ice may eventually be lost.
Is the 'pizzly-grolar' a new species?
No. At the moment all the bears are hybrids, not a new scientific species. It takes hundreds, or even thousands of years, for a new species to arise so we certainly won't see that happen in our lifetimes!
1
How is the polar bear specifically adapted to living in a cold environment?
2
Can you point out what features of the Pizzly comes from the polar bear and the grizzly bear?