Why did Homo sapiens outlast all other human species?

The endurance of Homo sapiens as a species and the extinction of other human relatives have long intrigued scientists. Through millions of years of evolution, our species emerged as the sole survivors among at least 18 different hominin species. The key to our success lies in a combination of factors and unique capabilities that set us apart.

Bipedalism, or two-legged walking, played a crucial role in the evolution of hominins. Although earlier species such as Ardipithecus and Australopithecus were also capable of bipedalism, they eventually vanished from the scene. As for the genus Paranthropus, their apelike characteristics, massive back teeth, and chewy muscles set them apart from early Homo species. Interestingly, Homo and Paranthropus coexisted for some time until Paranthropus eventually disappeared, leaving Homo to prosper and multiply across the globe.

The extinction of Ardipithecus, Australopithecus, and Paranthropus remains a mystery and likely arose from a combination of factors. Environmental changes, competition for resources among hominin species, and low population densities could have played a role. However, it is the evolution of larger brains within the Homo genus that proved advantageous. With bigger brains came improvements in cognition, toolmaking abilities, sociality, and problem-solving.

Homo species exhibited behavioral complexity, including activities like burial rituals, shelter construction, weapon development, and controlled use of fire. The emergence of specialization and diversified tools for various tasks contributed to increased adaptability and resilience. The reasons why Homo sapiens outlasted all other Homo species are not entirely clear, but evidence suggests that our cognitive abilities, technical skills, problem-solving capabilities, and flexible social strategies surpassed those of our extinct relatives. Moreover, our adaptability to diverse environments, both biologically and culturally through evolving technology and behavior, contributed to our success.

Additionally, chance events and serendipity played a part, as small population sizes could quickly decline due to natural disasters, diseases, or climate fluctuations. This created opportunities for other species—such as H. sapiens—to flourish.

The expansion of H. sapiens out of Africa led to encounters with Neanderthals in Europe and with Denisovans in Asia. Genetic evidence indicates interactions and possible competition between these groups. The success of H. sapiens in "moving around and mating" likely strained other species through resource competition.

While global climate change may have contributed to the extinction of some Homo species, the role it played remains uncertain. The survival of H. sapiens during the Ice Ages in Europe while Neanderthals adapted to cold conditions, perished suggests that climate alone cannot explain the full picture.

It is essential to acknowledge that even H. sapiens faced near-extinction at one point. Genetic studies reveal a population bottleneck that occurred between 813,000 and 930,000 years ago, reducing the global H. sapiens population to approximately 1,300 individuals for an extended period.

Our continued existence as a species is not guaranteed. Our flexibility, adaptability, and cooperative nature will be vital for confronting future challenges, ensuring our perseverance in an ever-changing world.

Earlier, SSP wrote about the study that revealed almost human-like abilities in rats.