Monkeys and squirrels are tree –dwelling. The chief adaptations of arboreal animals are:-
1. They have a strong body with a well developed pectoral girdle which supports the weight for the body.
2. Tail may be prehensile (capable of grasping) as is found in some monkeys. But in others tails are non-prehensile. Such tails have hairs and scales to prevent the animal from slipping, as in flying squirrel.
3. Hip girdle is broad as it has to support the body organs.