The monkey with the longest tail in world?

It's impossible to definitively say which monkey has the longest tail in the world.

Here's why:

* Variability within species: Even within the same monkey species, tail length can vary greatly based on individual genetics and age.

* Limited data: Precise measurements of tail length aren't commonly recorded for all monkey species.

* Different definitions of "longest": Do we mean the absolute length of the tail, or the length relative to the monkey's body size?

However, there are some contenders for the title, such as:

* Spider monkeys: These monkeys are known for their extremely long tails that they use as a fifth limb for swinging through the trees. Some individuals have tails that can be longer than their body length.

* Howler monkeys: Another group of monkeys with long tails. Their tails are prehensile (can grasp), just like spider monkeys.

Instead of focusing on the "longest" tail, it's more interesting to appreciate the diverse adaptations of tails among monkeys. Some use them for balance, others for communication, and some even for grasping and picking up food!