A survey on the grouping patterns of sympatric Przewalski's gazelle ( Procapra przewalskii
) and the Tibetan gazelle ( Procapra picticaudata
) was conducted from June to July and September, 2005 in the upper Buha river, Tianjun county, Qinghai province, China. Group types of the two Chinese endemic gazelles could be classified into female group, male group, mixed group and mother-offspring group. Of these four types, the male groups were 41% and 50% of the total in Przewalski's gazelle and the Tibetan gazelle, respectively. The female groups were 34% and 30% of the total in Przewalski's gazelle and the Tibetan gazelle, respectively. Sizes of different group types of Przewalski's gazelle were not significantly different, expect the mother-offspring groups (P=0.015). The frequency of solitary gazelles, 2-8 individuals and >9 individuals were 21.9%, 62.6% and 15.5% of the total in Przewalski's gazelle respectively and 18.7%, 67.6% and 13.7% of the total in the Tibetan gazelle respectively. While group sizes of the male groups and the mixed groups increased insignificantly after lambing, the female group size decreased significantly in both Przewalski's gazelle and the Tibetan gazelle (Przewalski's gazelle: P<0.001, Tibetan gazelle: P=0.002). Consequently, average group size decreased significantly in both gazelles (Przewalski's gazelle: P=0.014, Tibetan gazelle: P=0.008). There were no significant differences in group patterns between Przewalski's gazelle and the Tibetan gazelle during the green grass period.