I think I know why this monkey is so upset. It could be that it's got a
tooth ache. But more likely it takes umbrage with its name: stump-tailed macaque (Macaca arctoides).
Really, stump-tailed? Of all things you could have called it, why go
with that? Why not wrath-faced macaque? Why not luxuriantly-coated
macaque? Why focus on the one thing it is least proud of?

Personally,
I would have named it the 'mulletted macaque', but that would have
gotten me eaten. It's best for the safety of me and my family that I'm
not in charge of anything taxonomically oriented, especially when it
comes to fanged primates.
Source

Photo by Sebastian Niedlich