The monkeys are divided into two main groups—Old World and New World monkeys. The term “old world” refers to the areas (Europe, Africa, and Asia) known to the Europeans prior to the discovery of the “new world” (the Americas).  

• New World monkeys are members of five different primate families (Callitrichidae, Cebidae, Aotidae, Pitheciidae, and Atelidae) and consist of almost exclusively arboreal (tree-dwelling) species like marmosets, tamarins, capuchins, and spider monkeys.  
• Old World monkeys belong to the family Cercopithecidae and consist of species such as macaques, baboons, and vervet monkeys.  

• These monkeys spend much more of their time on the ground, but can be found in habitats ranging from the rainforest to the savannah to the mountains. 

Source: NCERT