The striped monkeys hang down from trees throughout the level and pelt you with fruit, you'll have to jump and charge them all.
The easiest way to deal with them is simply to walk to the side as they throw, they will each throw 4 fruit. After the 4th throw you'll have a window to jump and charge them safely. There are 8 in total.
Here are the locations
1. At the beginning of the level in a tree to the right.
2. Across the river to the left of the starting platform
3. Up the path in the tree behind the Spring powerup, behind the fountain
4. At the end of the path in the tree near the water.
5 & 6 On the upper canopy after going through the whirlwind, there will be 2 here.
7. Follow the canopy bridges to the end where one more will drop down
8. After defeating 20 enemies and activating the spring powerup, the final monkey will be in the tree closest to the exit portal.