Scientists speculate that primates lost their claws and turned to wide fingernails to assist in exercise. Because the ancestors of mammals climbed on tree trunks, claws can provide excellent grasping ability, while larger primates moved on smaller branches and climbed to the crown to collect fruits, so claws became troublesome. Primates, on the other hand, have evolved wide fingertips that are more suitable for them to grasp fruits.
About 2.5 million years ago, fossil evidence showed that early humans first picked up stones as tools, and at the same time, our ancestors evolved into wide fingertips earlier than other early primates. Nowadays, humans can show off their fingertips more than other primates.
Fingernails are about 2.5 cm long every month, and the whole nail can be completely updated in 6 weeks. Hawkes said it is not clear whether nails adapt to the side effects of helping to support wide fingertips or losing claws. Another reason why we have nails is that they can be used as a billboard for a person's health. For example, malnutrition can change the color of nails, and small depressions on nails are signs of psoriasis on the skin. Nails are also a symbol of beauty and power.