What is the fiercest monkey?

It's impossible to definitively say which monkey is the "fiercest" as "fierceness" is subjective and depends on what criteria you're using to define it. Different species have different strengths:

* Aggression: Mandrills are known for their fierce displays and intimidating size, but are primarily territorial and rarely aggressive towards humans. Baboons are also very aggressive, especially in large troops, and can be dangerous to humans.

* Strength: Gorillas are the largest primates and are incredibly strong, but generally prefer to avoid conflict. Orangutans are also strong, but are mostly solitary and not known for aggressive behavior.

* Fighting skills: Proboscis monkeys have been observed engaging in "mock fights" with impressive agility, but these are mostly for social dominance and not truly aggressive.

Ultimately, it's important to remember that each monkey species has its own unique characteristics and behaviors, and labeling one as the "fiercest" doesn't accurately represent their complexity.

Instead of focusing on a singular "fiercest" monkey, it's more interesting to learn about the diverse behaviors and adaptations of different primate species.