From The TimeSplitters Wiki

Monkey
Unlocked by	Default
Species	Animal
Size	Small
Accuracy	6
Agility	10
Stamina	2
Fire Proof	5
Shock Proof	5
Default AI	1
Native TimeZone	1920
First Appearance	TS2 Story Mode
Relations	Brains, Cyborg Chimp, Ninja Monkey
Games	TS2, TSFP

TS1 Gesture	N/A	TSFP Gesture	Hops down and does a flip.
TS2 Gallery	It's a monkey.	TSFP Gallery	Yep, it's still a monkey.

The Monkey has been a recurring character in the TS series. Free Radical Design has been said to have a fetish with this character.

1920 Aztec Ruins

The Monkey is encountered in this mission as an enemy that stands still and throws explosive melons. Their small size can make them difficult to spot, and their melons do considerable damage which can make them a dangerous foe.