Black bear cubs

I was watching a nature programme last night - "Seven Worlds, One Planet". There were two Black bear cubs and their mother on the coast of Vancouver Island.  The cubs were standing up on their hind legs some of the time and looked so adorable. Their mother was teaching them how to lift rocks to catch and eat the crabs underneath. They had to run up a tree when a large male came lumbering along but he didn't pursue them, just marked the tree as a warning to them that this was his territory and to go somewhere else. 

Jane