In Neocene Atlantic Ocean had continued to extend, and, as if a wedge, had separated North and South Americas, having broken off isthmus of Panama. South America has moved little bit closer to South Pole, and it has resulted in expansion of temperate climate area and pampas – plain areas covered with grassy vegetation. In pampas herds of large animals wander – huge tapirotheriums, descendants of tapirs little bit similar to elephants, deermaras and giant paca – cursorial caviomorph rodents. They are pursued by hunting heron, large flightless bird, and also by – the heaviest flying bird of the world. Among smaller animals inhabiting pampas, rodents, armadilloes (including rather large species) and numerous birds are characteristic. Among South American inhabitants of pampas monkeys are lack – not so numerous ground New World monkeys prefer to stay in woody regions and bushes. Original pampas analogue of baboons and other ground monkeys of Old World is the representative of raccoon family adapted to life in grassy plains – flag-tailed pampanasua. It is the descendant of one species of coatimundi (Nasua), successfully adapted to life in forestless areas after disappearance of significant part of South American forests as a result of human activity. Compared to its ancestors, pampanasua has changed in significant degree. It is long-legged animal of gracile constitution about 60 cm high at a shoulder; body length of adult individual is up to 70 cm, not including tail. The body of pampanasua is covered with rusty-red wool with small dark spots on back and sides. Muzzle is long and has a mobile nose and well advanced olfactory chambers. Due to keen sense of smell pampanasua easily finds insect larvae and edible parts of plants under ground at the depth of about 20 cm. Fingers of animal are short, but mobile, and claws are blunt: this animal swarms up trees worse, rather than its ancestor, and spends almost whole life in open areas where it moves on four paws more often. In order to look around pampanasua can rear on hind legs and keep vertical position within several minutes. For recognition of relatives this animal has contrast marks on muzzle: forward part of muzzle is white with black “glasses” around of eyes. The size of these “glasses” depends on testosterone content in blood, and at dominant males they are especially large. The size of marks allows quickly establishing of hierarchical relations, not resorting to combat. Males have long canines which tips stick out of the closed mouth. Defending itself from the enemy, pampanasua puts very painful bites. Ears of pampanasua are long and have white hair brushes on tips. Auricles serve for removal of superfluous heat from organism. Pampanasua lives the groups numbering up to 20 members – males and females of various ages. Animals communicate with each other with the help of various sounds – hissing, snorting, cooing and grunting. For communication with congeners at the long distance this species uses tail reaching 1 meter length. In the basis of tail pale cross-sriped pattern is visible, and on the tip the one-sided brush of lengthened hair of white color is developed; tail tip is black. In rest animal holds tail vertically and its movements are smooth. Quivering tail is the feature of alert animal. Usually animals signal this way to each other about snake found out. Pampanasua submits alarm signal in the voice – it is a series of abrupt shrill sounds similar to bark of small dog. Usually pampanasua moves on the ground, but also can clamber on trees. The main enemies of these animals are hunting herons. Pampanasua hides from them, dropping to the ground and drawing tail in, or getting on trees. The group can frighten off a medium-sized single predator with menacing demonstrations. Pampanasua is omnivorous and equally willingly eats food of vegetative and animal origin. Animals dig out tubers and bulbs, eat sapful bases of leaves of grasses, young shoots of bushes. Among food of animal origin pampanasua prefers insects, small reptiles and nestlings of ground birds. Frequently the group of pampanasua keeps near to large rodents and tapirotheres, and catch near them frightened insects and small reptiles. Due to keen sight and good hearing pampanasua right in time distinguishes approaching of enemies and warns large animals of their occurrence. Twice per one year the female gives rise to one or two cubs. As this species leads migrating habit of life and does not build long-term shelters, the female must carry her posterity herself. The cub is born blind and covered with short wool. Right after birth it is able to cling to wool of mother and to twist her tail with its one. Due to it cub does not fall on the ground even if the female darts off sharply. Cub’s eyes open at week age, and at the age of one month young animals spend a significant part of time on the ground, getting on mother’s body only at the alarm signal. At one-year-old age young animal leads independent life. Males usually stay in parental clan, and females pass from one clan to another. Sexual maturity comes at the age of two years, and life expectancy reaches 25 – 30 years.