1. The Brain
Having a big brain is usually synonymous with being smart, but it’s also a sign of a longer life ahead. Relatively speaking, humans have much larger brains than their animal counterparts. These bigger brains use a huge amount of energy and take a long time to develop, resulting in a slower journey to sexual maturity and far smaller numbers of reproduction. Unlike the animal kingdom, humans also don’t face as much pressure to die early, as overpopulation is less of a concern. Animals with smaller brains can grow faster, meaning their typical survival strategy is to reach sexual maturity quickly and breed quickly in much greater numbers.