Explanation:
The pinnae, also known as the external ears, are the visible part of the ear that helps in collecting sound waves and funneling them into the ear canal. In humans, the pinnae are not capable of voluntary movement. The muscles responsible for moving the pinnae are either absent or vestigial, which means they are present but are not functional.

Absent Muscles:
The muscles that are responsible for moving the pinnae in some animals, such as dogs and cats, are absent in humans. These animals have a more developed and movable pinnae structure that allows them to change the direction of their ears to better capture sounds. However, humans do not possess these muscles, and therefore, cannot move their pinnae in the same way.

Vestigial Muscles:
While humans do not have the muscles necessary for moving the pinnae, they do possess vestigial muscles that are remnants of the evolutionary process. These muscles are remnants of the muscles that were once used by our ancestors for ear movement. However, these muscles have lost their function over time and are no longer capable of moving the pinnae in humans.

Functional Importance:
Although the muscles for moving the pinnae are absent or vestigial in humans, it does not significantly impact our hearing abilities. The shape and position of the pinnae in humans are already optimized for capturing sound waves and directing them into the ear canal. The absence of movable pinnae does not affect our ability to perceive sound or locate its source accurately.

Conclusion:
In conclusion, the muscles that move the pinnae in humans are either absent or vestigial. While some animals can actively move their pinnae to enhance their hearing capabilities, humans do not possess this ability. Nevertheless, our hearing is not compromised as the shape and position of our pinnae are already optimized for effective sound collection.