How is a rats upper lip different from a human?

A rat's upper lip is more flexible and mobile compared to a human's, allowing for a greater range of movement, which aids in their ability to manipulate food and groom themselves. Additionally, rats have a pronounced whisker pad that enhances their sensory perception. In contrast, humans have a fixed upper lip that plays a key role in speech and facial expressions. Overall, the anatomical structure of the upper lip in rats is adapted for their specific behaviors and survival needs.