Final answer:
New World Monkeys are characterized by having prehensile tails, broad round nostrils, a tendency for pair bonding, and an exclusively arboreal lifestyle.
Step-by-step explanation:
The main characteristics that define New World Monkeys, which set them apart from Old World monkeys, include the following:
- Prehensile tails: Most species have a grasping tail that acts as an extra limb for additional support in their arboreal habitats.
- Broad, round nostrils: Their nostrils are rounded and open to the sides, which is distinct from the narrow, downward-facing nostrils seen in Old World monkeys.
- Pair bonding: Unlike most Old-World monkeys, New World monkey species such as tamarins and marmosets often form monogamous relationships and cooperatively raise their young.
- Arboreal lifestyle: All New World monkey species are tree-dwellers, which influences their physical adaptations, such as their limbs and tail.
New World monkeys exhibit these unique characteristics due to their evolutionary history and geographic separation from their Old-World counterparts.