>>>>>As the old latin proverb goes, "wolf changes hair, not the character" (although in the Svetonius's book it's a fox - "vulpes pilum mutat, non mores").
>>>>
>>>>In dutch: A fox would lose its hair, but not its character.
>>>
>>>In English : A leopard doesn't change it's spots
>>
>>its spots.
>
>In English: Nits never stop picking :-}

:) I can't help it. There is no Russian saying I can remember of here either.