Five vestigial features of the human body:
1. Palmar grasp reflex, a grasping reflex seen in unborn children and newborns, possibly an evolutionary trait intended to help infants cling to their mothers.
2. Tails. In the first six weeks of gestation, the human embryo possesses a tail, complete with several vertebrae. By birth, the tail has disappeared and the vertebrae fused to form the coccyx or tailbone.
3. Wisdom teeth, which were useful in early hominids who needed to grind hard foods. Modern humans have smaller jaws and eat softer foods, causing wisdom teeth to be unnecessary and often problematic.
4. In other animals, the nictitating membrane is a fold of tissue in the inner corner of the eye that serves as a sort of third eyelid, providing protection and cleaning. In some species, it can even cover the entire eye, yet is transparent enough for vision. In humans, it’s just an extra bit of tissue where “sleep” deposits.
5. Auricular muscles control the pinna or visible part of the outer ear. In other mammals, they are used to move the pinna to better zero in on incoming sounds or as a means of expression. In humans, they are mostly useless, though some people retain their ability to wiggle their ears.
