Useful Then, Useless Now Ever wonder why you get goosebumps in reaction to scary or emotional events? Or why your hands and feet get wrinkly when in water too long? These are examples of vestigial features, which are structures or attributes that have apparently lost most or all of their function in a given species. It’s fascinating to think about how humans have evolved and will continue to do so as the need for some bodily parts and functions disappear in modern life. Check out these five interesting examples:

Third Row Molars/Wisdom Teeth: If your wisdom teeth have been impacted or you’ve had them removed, you know just how painful this can be. There’s usually no room for them and they aren’t necessary for everyday eating and chewing. So why do so many people grow them in? Researchers say earlier species of humans likely needed these teeth to chew and grind tough plant material they ate to survive. Modern humans don’t need this feature, and approximately 10-25 percent of Americans are born missing at least one wisdom tooth, which may be a sign of evolution or brought on by a genetic mutation.

Pruney Hands and Feet: Spend just a little too much time in the pool or bathtub and your fingertips and pads of your feet get all pruney-looking. What’s the point of this reaction beyond puzzling and delighting toddlers? Scientists believe this phenomenon made hand and foot traction better for climbing and provided stronger and faster grip when our predecessors gathered food from wet vegetation and streams.

Useful Then, Useless Now

Arrector Pili/Goosebumps: Arrector Pili are the smooth muscle fibers that involuntary contract when we’re cold, excited, sad or scared. However, goosebumps serve no known purpose for modern humans. Researchers believe goosebumps are a reaction evolved from our animal ancestors, who benefited because it made their hair stand up; which not only provided additional insulation, but gave the appearance of a larger body—a very important feature in the defense against predators.

The Appendix: This organ is probably the most well-known of vestigial organs; however there is some debate the appendix may serve the purpose of storing helpful bacteria. Approximately 250,000 Americans have their appendix removed each year and go on to live healthy lives. Beyond bacteria, is there a reason why we’re born with them? Experts think our appendices were once larger and aided our ancestors in digesting the cellulose-rich plants our wisdom teeth helped chew.

The Palmar Grasp Reflex: This is the extremely strong, reflexive grasp babies have in their hands and feet until about five months old. It’s adorable when they cling to our fingers to be sure, buy why do they do it? Get ready to say, “Ah-ha”—this one may date back to our very earliest ancestor infants who needed to hold on tight to their mother’s hair-covered backs and chests while being carried around.