Abstract: 1.Four methods have been developed for following and closing with the group (s) of Rh-inopithecus bieti and the author had taken the normal behavioral samples in the field. It isespecially indicated, however, that measuring behavior is only one of the three important as-pects of answering behavioral questions. The other two should be, (1) answering how one canclose with the subject (s), and going into details of his approaching procedures; (2) testing his hypothesis by an appropriate statistical test. Not a single one of the three aspect can be dis-pensed with answering any behavorial question.
2. A key parameter Q was founded standing for the .. ratio of one type of vegetable be-tween residues in dung (X) and food taken by animals(Y), and further, a formula ?=(l/Q)X was founded for reliably calculating the a verage volumes of types ofherbivorous dietstaken by a group of R. bieti in the wild during a period. The Q should be the best parameterof today for study of the amounts of herbivorous food taken by monkeys in the wild.
3. Through feeding 'behaviorsurveyed in wild and captivities and its excrements identi-fication, the principal diets for Rhinopithecus bieti were classified as three types as follows:(1) Leaves and stems of Monocotyledoneae, esp ecially Gramineae which hasparallel vascularbundles and prickles: (2) Some species in Lichens which has hyphae interwinded each otherand coming into mycelium; (3) Small buds, barks, stems and fruitsof angiospermous trees.However, for the first time, leaves of Abies sp., Picea sp., and other conifers are not consider-ed as diets for R. bieti. For these reasons, R. bieti has more adapted humidly tropical and sub-tropical angiosperm enviroment than vegetational zones of Abies and Picea in high and cold orsnowy mountains. According to the results, R. bieti's principal habits should be terrestrial and itsevolutionary stage has been shifting from the tropical forest into the open woodland and gr-assland. Therefore, the causes of formation of this monkey's distribution in high and cold orsnowy mountains needs more research.

Key words: Rhinopithecus bieti; Feedingbehavior; Types of diets; Parasites