12 Differences Between Old and New World Monkeys.

1. FAMILY:

Old World monkeys belong to the family Cercopithecidae whereas new world monkeys are five families of primates: Callitrichidae, Cebidae, Aotidae, Pitheciidae, and Atelidae.

2. LOCATION:

The old world refers to Europe, Asia, and Africa and these monkeys live in Asia and Africa whereas the new world refers to the Americas and these monkeys inhabit the tropical regions of Mexico, Central, and South America.

3. FACIAL FEATURES:

Old World (Common Chimpanzee) and New World (Red-Faced Spider Monkey) Monkey Faces.

Old World Monkeys are catarrhines which means they have a downward-facing nose and nostrils are closer together whereas New World Monkeys are platyrrhines which means they have a broad and flat nose with nostrils facing sideways.

4. BODY SIZE:

Old World Monkeys are medium to large-sized monkeys whereas New World Monkeys are small to medium-sized monkeys.

5. TAIL:

A black and gold howler monkey hanging by its prehensile tail.

Old World Monkeys have a non-prehensile tail whereas some species of new world monkeys have a prehensile tail which they wrap around a tree branch to hang from it.

6. PREMOLARS

Old World Monkeys have two premolar teeth whereas New World Monkeys have a total of three premolar teeth.

7. FINGERS

Old World Monkeys have fingernails and toenails whereas New World Monkeys often have claws on their digits. Some species like marmosets and tamarins are exceptions.

Old World Monkeys have opposable thumbs while New World Monkeys do not possess opposable thumbs.

8. INFANT CARE

A mother Allen's swamp monkey(Old World Monkey) with a baby on her belly.

Image Credit: nationalzoo.si.edu

The male OldWorld Monkeys are not involved in infant care and it belongs entirely to the females. The babies are usually carried on the mother’s belly.

A squirrel monkey(New World Monkey) with a baby on her back.

Image Credit: zooborns,com

The male New World Monkeys are usually involved in infant care. The babies usually ride on their mother’s back.

9. DIET

Old World Monkeys rely more on leaves and grasses whereas New World Monkeys rely more on fruit.

10. ADAPTATION TO THEIR HABITAT

Most Old World Monkeys spend their time on the ground but their habitats range from savannah to rainforests to mountains whereas New World Monkeys are usually arboreal(live on trees).

11. ECTOTYMPANIC TUBE

Source: Chegg

Old World Monkeys possess a bony ear tube called an ectotympanic tube whereas New World Monkeys lack an ectotympanic tube.

12. ISCHIAL CALLOSITIES

Ischial callosities on an Old World Monkey.

Source: Wikipedia

Old World Monkeys have thickened layers of tissue called ischial callosities or sitting pads on their rears whereas New World Monkeys lack ischial callosities or sitting pads.