The pygmy marmoset is indeed the world's smallest monkey and is approximately the size of a toothbrush in height.
True
The world's smallest monkey—the pygmy marmoset—is about as tall as a toothbrush.
Pygmy Marmoset - San Diego Zoo Animals & Plants
Source: animals.sandiegozoo.org
At a glance
Verified August 3, 2025Key Evidence
Twycross Zoo states pygmy marmosets are about 13 cm long and newborns are about the size of a toothbrush head.
twycrosszoo.orgtwycrosszoo.orgPygmy marmoset
2 inches (approximately toothbrush length) and weight about 100 grams.
en.wikipedia.orgen.wikipedia.orgPygmy marmoset
reddit.comreddit.comr/Awwducational on Reddit: The pygmy marmoset is smallest marmoset and the...
The reporting
What the Evidence Shows
The pygmy marmoset, native to the rainforests of the western Amazon Basin in South America, holds the distinction of being the smallest monkey species in the world. Adult pygmy marmosets typically measure about 13 to 15 centimeters (approximately 5 to 6 inches) in body length, excluding their tail, which is longer than their body. This size is comparable to the length of a standard toothbrush.
Additionally, newborn pygmy marmosets are even smaller, roughly the size of the head of a toothbrush. Multiple reputable sources confirm this size comparison, emphasizing that the pygmy marmoset's diminutive stature makes it unique among primates.
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