While humans may be one of the few animals that can give a high five, they are one of many with five fingers and toes.
Humans are part of the primate family, which also includes monkeys, apes, and even lemurs. As a member of the family, you also have fingernails instead of claws and pads on your fingertips that help with your sense of touch.
![Sian Ritchie.](https://wpcdn.web.wsu.edu/wp-cas/uploads/sites/648/2018/12/ritchie_sian.jpg)
We actually see a total of ten fingers and toes in a lot of other vertebrates – animals with backbones. Fossil evidence of some early vertebrates show that some creatures had six, seven, or even eight fingers. That’s what I found out from my friend Sian Ritchie, who teaches biology at Washington State University.
Ritchie told me how animals tend to keep the characteristics or traits that help them survive in an environment. These are called adaptations. They may also over time lose some traits, like a finger or two.