A "herd" refers to a group of animals that live and move together, often for social or protective reasons. Common examples of herds include cattle, elephants, and deer. Herding behavior helps animals find food, avoid predators, and care for their young. Herds can vary in size, from small groups to large gatherings of hundreds or thousands of individuals. The social structure within a herd can be complex, with hierarchies and roles that help maintain order. This collective behavior is essential for the survival of many species in the wild.