This is the smallest primate on the planet
Pygmy marmosets are renowned as the smallest true monkeys, measuring from 117 to 152 mm (4.6 to 6.0 in) in head-to-body length and sporting tails ranging from 172 to 229 mm (6.8 to 9.0 in). On average, these adults tip the scales at just over 100 g (3.5 oz), with females slightly outweighing males, representing the sole sexual dimorphism.