The animal on the cover of Ajax on Java is a cotton-top tamarin (Saguinus oedipus), a small-bodied monkey characterized by the fan of long, white hair on its head. Tamarins are divided into three groups based on facial hair. The cotton-top is marked by thin hair on its black-skinned face such that its face appears naked. This puts it squarely into the bare-face group, as opposed to the hairy-face or mottled-face group. Tamarins have claw-like nails resembling those of a squirrel rather than flat
nails like other primates, which they use to cling, run, and leap through trees. They can do this with great ease due to their size: cotton-tops weigh less than one pound and reach only nine inches in height.
Cotton-top tamarins are found in a small area of northwest Colombia. Their range is bound by the Cauca and Magdalena Rivers and the Atlantic coast; however, they are currently found only in parks and reserves throughout this area. A group of tamarins maintains a fixed territory within its home range, which it chooses based on fruit availability. Other sources of nourishment for the tamarin include insects, plant exudates, nectar, and occasionally reptiles and amphibians. Most groups appear to be monogamous, with only one reproductively active male and female. Cotton-tops,like other members of their subfamily (callitrichines), primarily give birth to nonidentical twins. As its scientific name indicates, the male tamarin seems to have an Oedipus complex, yet the mother does not allow this relationship to be consummated.