What are the worlds smallest primates?

The title of "world's smallest primate" depends on what metric you're using:

By weight:

* Pygmy Marmoset (Cebuella pygmaea): This tiny monkey weighs just 100-150 grams (3.5-5.3 ounces) and is considered the smallest monkey in the world.

By height:

* Madame Berthe's Mouse Lemur (Microcebus berthae): This nocturnal lemur from Madagascar measures only 92 millimeters (3.6 inches) in length and weighs just 30 grams (1 ounce). While slightly heavier than the pygmy marmoset, it is considered the smallest primate by length.

Therefore, both the Pygmy Marmoset and Madame Berthe's Mouse Lemur could be considered the world's smallest primate, depending on the measurement used.