Monkey mandrill, almost long and weighing up to . Some are arboreal (living in trees) while others live on the savanna; diets differ among the various species but may contain any of the following: fruit, leaves, seeds, nuts, flowers, eggs and small animals (including insects and spiders). Some characteristics are shared among the groups; most New World monkeys have prehensile tails while Old World monkeys have non-prehensile tails or no visible tail at all. Old World monkeys have trichromatic color vision like that of humans, while New World monkeys may be trichromatic, dichromatic, or—as in the owl monkeys and greater galagos—monochromatic.
Vicente Pérez Rosales National Park reeds. A diversity of animals of the rodent group live in the park. The larger ones are coipo, coypu, "Myocastor coypus", a webbed-feet animal that inhabits reedy lake and river banks; and Wolffsohn's viscacha, "Lagidium wolffsohni", of the family Chinchillidae, whose preferred habitat is above the timber line. Among the smaller rodents, scientists have shown particular interest for Chilean climbing mouse, "Irenomys tarsalis", and for the long-clawed mole mouse, "Geoxus valdivianus". The park is home to two species of marsupial mammals. Monito del monte, "Dromiciops gliroides", has a semi-arboreal habit. It has been discussed why this South American marsupial appears