They were often kept alongside dairy cattle herds. Ranchers wanted the buffalo gone to open pasture land for their cattle herds. He used the land for cattle and sheep herds. Outbreaks are known to occur in cattle herds. Bison are nomadic grazers and travel in herds. As in other wild cattle ungulates that form unisexual herds, considerable sexual dimorphism was expressed. Hunters were hired to provide buffalo meat from the large herds of American bison. Leopards are resident at places where wild animals are abundant, and follow herds of ungulates. It was more appealing to me than herds of cattle. Disturbance by and interbreeding with livestock herds is also common. The migrations of Porcupine caribou herds are among the longest of any mammal. European bison herds are not family units. Large herds of buffalo and elephant total about 30,000 beasts. Duke is clearly no match for the intellect possessed by the sheep he herds. They are generally social animals that live in small harems to large herds.