Final answer:
Animals, including dinosaurs, primarily move to obtain food, which is critical for survival. Locomotion also assists with escaping predators, finding mates, and sometimes defending territory. For bipedal dinosaurs, long tails were necessary for balance while moving.
Step-by-step explanation:
One of the principal reasons most animals, including dinosaurs, locomote is to obtain food. This is a fundamental need, as animals require energy to survive, grow, and reproduce. In the process of gathering and hunting, animals move about to find resources that are readily available in their environment such as fruits, nuts, and prey. Additionally, locomotion is necessary for other critical aspects of life, namely evading predators, finding mates, and sometimes maintaining territory.
Locomotion also enables animals to adapt to their environment in various ways, such as migrating to more favorable conditions or expanses with richer food sources. For bipedal creatures, such as some dinosaurs, having a long tail provided balance, especially if they possessed long necks. This balance would be essential in both predator evasion and hunting. Overall, locomotion is central to an animal's ability to thrive within its ecosystem.