A leopard cannot change its spots
What's the meaning of the phrase 'A leopard cannot change its spots'?
The notion that things cannot change their innate nature.
What's the origin of the phrase 'A leopard cannot change its spots'?
From the Bible, Jeremiah 13:23 (King James Version):
"Can the Ethiopian change his skin, or the leopard his spots? then may ye also do good, that are accustomed to do evil."
See also: the List of Proverbs.