How can scientists tell that all polar bears are left handed because they don’t even write????!!

Question: How can scientists tell that all polar bears are left handed because they don't even write????!!
- Keywords:
  bear,
  left handed,
  polar bear
Asked by akukharuk99 to Charlotte, Jo, Kevin, Louise, Valeria on 19 Jun 2012. This question was also asked by jessc.
- Kevin Mahon answered on 19 Jun 2012:
  
  A myth again I’m afraid!
  
  Great white bears are not left-pawed. Scientists observing the animals haven’t yet noticed a preference. In fact, polar bears seem to use their right and left paws equally!
- Valeria Senigaglia answered on 19 Jun 2012:
  
  However to answer the question on how they can tell:
  
  Being left or right handed means you have a preference in using one hand or the other so you can be left handed even without write.
  Said that…Kevin is right, is a myth.
- Joanna Cruden answered on 19 Jun 2012:
  
  It would be easy to see if a monkey was left or right handed, in the same way as we can for humans, the more you study animals you more you notice things and the more you realise how fascinating they are 🙂

Question: How can scientists tell that all polar bears are left handed because they don't even write????!!