A shepherd is a person who herds flocks or groups of animals. If you traveled to Tibet, you might see a yak shepherd.
Shepherd comes from the Old English sceaphierde: sheepherder. Such a person protects sheep from animals that would attack them, keeps them from wandering, and otherwise takes care of the flock. The word is also a verb that describes care of a group — sheep, other animals, even people. You might shepherd your herd of goats, or shepherd your younger siblings through the transition from elementary to middle school.