Is the white and black ruffed lemur old world monkey?

No, the white and black ruffed lemur (Varecia variegata) is not an Old World monkey. It is a lemur, which belongs to the primate infraorder Lemuriformes.

Old World monkeys are part of the infraorder Catarrhini, which also includes apes. Lemurs, on the other hand, are part of the infraorder Strepsirrhini, which are more closely related to lorises and galagos.

Here's a breakdown:

* Old World Monkeys: Belong to the Catarrhini infraorder, found in Africa and Asia.

* Lemurs: Belong to the Strepsirrhini infraorder, found only in Madagascar.

So, while both lemurs and Old World monkeys are primates, they belong to different infraorders, meaning they evolved along separate branches of the primate family tree.