2004年11月～2005年10月，在贺兰山对岩羊（Pseudois nayaur）的集群行为进行了研究，将其集群类型划分为雌性群、雄性群、雌雄群、母仔群、混合群和独羊6种类型。共观察到岩羊1 023群次，计4 866只次，平均群大小为(4.86±2.54)只，最大的群为51只，最小的为独羊。其中，母仔群459群（44.87%）为最多的集群类型，其余为混合群（20.72%）、雄性群（14.86%）、独羊（9.09%）、雌雄群（5.57%）、雌性群（4.89%）。母仔群出现的频次在4个季节均最高，除母仔群外，春季雄性群出现的频次最高，而夏、秋、冬季都是混合群出现的频次最高，不同类型集群出现频次的季节间差异极显著。在4个季节中都以2～5只的群居多，其出现的频次占各季节群数50%以上，不同季节群大小差异极显著，而不同集群类型群大小季节间不存在显著差异。除独羊外，不同季节混合群大小差异极显著，母仔群、雌性群大小差异显著，而雄性群、雌雄群大小无显著差异。研究结果显示，贺兰山岩羊集小群是其显著特点，随着季节的变化，其集群类型、集群大小均会发生一定的变化。
We studied group types and sizes of blue sheep (Pseudois nayaur) in the Helan Mountains from November 2004 to October 2005. Blue sheep groups were observed with KOWA 8×42 DCF binoculars and a KOWA TSN-824 M power spotting scope. Groups were classified as female, male, male-female, ewe-lamb, mixed groups, and solitary sheep. A total of 4 866 sheep belonging to 1 023 groups were observed, with a mean group size of 4.86 (SD=2.54). The largest groups included 51 sheep and the smallest groups were solitary sheep. Ewe-lamb groups were the most frequently encountered, constituting 44.8% of total observations. Mixed-sex groups, male groups and solitary sheep made up 20.72%, 14.68%, and 9.09% respectively of total observations. Male-female and female groups made up 5.57% and 4.89% of total sheep classified. Ewe-lamb groups predominated in all seasons, but frequencies of observed group types varied seasonally (P<0001). Male groups were more numerous in spring than in other seasons, whereas mixed groups were least in spring, increasing through summer, autumn, and winter. Groups consisting of 2-5 individuals dominated in all seasons, and constituted 50% of total groups observed. Group sizes varied seasonally (P<0.001), but mean group size did not differ seasonally. There were significant seasonal variations in group sizes of mixed-sex (P<0.001), ewe-lamb (P<0.05), and female groups (P<0.05). Seasonal variations in sizes of male and male-female groups were not significant. Small herd sizes are characteristic of the blue sheep in the Helan Mountains.