A normal series of calls by a pygmy marmoset contains approximately 10 different call types. There are a total of 16 call types in pygmy marmoset babbling language. The pygmy marmoset and tassle-eared marmoset are shown. This is smaller than the world's smallest monkey, the pygmy marmoset, which ranges between . For these reasons, pygmy marmoset calls are seen as babbling behavior. The pygmy marmoset changes the characteristics of its calls when its social environment is changed. The pygmy marmoset walks on all four limbs and can leap up to between branches.