Pygmy marmosets are part of a group that has claws/digits. They have a nail on the big toe only. Pygmy marmosets are the smallest primates in the world. New born babies weigh only half of an ounce. In two years they reach adult size and maturity, weighing three ounces. A full grown adult can weigh up to five ounces (which is over 130 grams). The body length is between 130 to 370 mm [5-14 inches] and its tail is between 150 and 420 mm [6-15 inches]. The forelimbs are shorter than the hind limbs.

          The fur on the pygmy marmoset is thick, and the under side is usually orangish, although it can range from white or tawny. The tufts of hair that looks like a mane are usually dark brown or gray. The long tail of a pygmy marmoset is ringed, but not prehensile.

          Pygmy marmosets have two molars, but most other monkies have three. Pygmy marmosets are short-tusked or have only slightly longer canines than incisors. There is nowhere that says they have wisdom teeth so we can conclude that they do not. Except for their genitals, pygmy marmosets of different sexes are similar in appearance. The eyes of pygmy marmosets are hazel and brown, they only vary slightly.

Largest Birth Weight!
          Pygmy marmosets are actually the largest of something! They have the largest birth weight compared to the mother, of any monkey. Think of humans for example, the average woman weighs 150, and the average baby weighs about 8 pounds. That is about a 19th of the woman's weight. The baby pygmy is only a 6th of the Adult pygmy's weight.

          Now to see how small Pygmy Marmosets really are, here are two pictures of their skulls! Gross, I know, but see that quarter by the skull? They are really small.But look at how big the cavity is where their brain goes! They have big brains in those little heads.