Discover how a simple test on your wrist with your pinky can reveal fascinating evidence of human evolution via the presence of this tendon.

Many internal and external features we possess are merely remnants inherited from our ancestors. These traits often no longer serve a practical purpose in our modern lives. As people no longer need to scavenge for food or live as nomads, we still carry these almost obsolete characteristics, passed down from a time when they were essential for survival.

Take, for instance, the curious phenomenon of goosebumps

This isn’t just a random occurrence. Our mammalian ancestors had a way of dealing with cold temperatures. Goosebumps helped them increase their surface area to retain heat. When we’re cold, a muscle attached to our arm hairs contracts, making the hairs stand upright and creating bumps on our skin.

While this response no longer serves a significant purpose in our lives today, it still reminds us to grab a coat on a chilly day. We can observe modern mammals engaging in this biological instinct, such as a pigeon puffing up its feathers to stay warm on a cold winter day. If that isn’t evidence of evolution, what is?