How Did Homo rudolfensis Survive in East Africa Nearly 2 Million Years Ago, and Why Did They Eventually Go Extinct? — Here’s What Experts Believe

Long before the modern human species existed on this planet, there were already several other hominins that walked, survived, and went extinct. One of those species is Homo rudolfensis. They are a human relative who was believed to have lived on the lands in East Africa nearly 2 million years ago.

However, they are also one of those species that have not met and interacted with modern humans, as they were already long gone before we even evolved about 300,000 years ago. But their fossils and geological studies left some clues that we can delve into to find out and imagine how they could’ve survived and why they eventually went extinct.

What We Know — Fossils, Anatomy, and Habitat

Homo rudolfensis lived approximately around 2.5 million to 1.8 million years ago, and researchers found this out by discovering one of their fossils near Lake Turkana in Kenya, which was once called Lake Rudolf. This is where the species got its name. The remains that were found were mainly comprised of their skulls, teeth, and jaws.

Around the time of their existence, other hominins were already roaming the planet, such as Homo habilis. However, compared to them, Homo rudolfensis had a larger braincase, which is a part of the skull that directly protects the brain, and they also had huge molar teeth.

This meant that Homo rudolfensis could have had bigger brains than hominins like Homo habilis. While it does not necessarily imply that they are smarter, it still could mean that they have more cognitive capabilities, but not as big a gap. One important clue, though, is their teeth and enamel, which suggest that they may have had a more diverse diet that includes harder-to-chew foods. From this discovery, scientists could infer how they survived in the changing environment of Africa millions of years ago.

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How They Could Survive — Diet, Flexibility, and Tool Use

Homo Rudolfensis: Humanity’s Forgotten Ancestor | Prehistoric Humans Documentary

The environments believed to be Homo rudolfensis’ main habitats in East Africa about 2 million years ago are woodlands, open savannas, and areas near rivers. Based on their fossils, they possibly ate both meat and plants to survive. The robust thickness of their tooth enamel and molars suggests the food they consumed was tough, like underground roots, fruits, and animal meats.

At around this time, the use and control of fire had not yet been discovered or was not prevalent, which is probably why they needed those larger teeth and strong jaws to bite through the tougher food sources. Additionally, although they existed around the same time as the Oldowan stone tool industry, the direct evidence of their stone tool usage is minimal.

But during their existence, many other hominins were already using basic stone tools to cut through meat and even obtain the marrow inside. So, it is plausible that Homo rudolfensis may have also utilized these abilities, and the fossil evidence was just not found.

Overall, these features all point to their dietary flexibility, which may have played the most significant role in their long survival. It meant that if the environment shifted and their natural habitats changed, they would be able to move and obtain resources to eat a variety of foods.

Challenges and Pressures — Climate, Competition, and Habitat

Even with the dietary and ecological flexibility of Homo rudolfensis, they still faced challenges that they would soon not be able to overcome as a species. One of the biggest is climate change. Around 2 million years ago, Africa grew drier, where open areas like savannas, deserts, and grasslands expanded, and the forested areas receded.

This meant that the natural habitat of Homo rudolfensis was increasingly becoming scarce in resources and inhospitable. Water sources could have dried up, and vegetation became more limited, causing a decrease in plant and meat food sources. This made life a lot harder for species that rely on their natural habitats to provide the necessary resources to survive.

Additionally, the other hominins, like Homo erectus, were also in the same area competing with them for the same decreasing resources. Unlike Homo rudolfensis, these other species have direct evidence of stone tool usage and are probably more advanced than them. So, if two species compete, there is a big chance that one of them could be outcompeted, and that means this species could be headed into the path of extinction.

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Why They Eventually Went Extinct — Possible Scenarios

Early Genus Homo: Homo habilis and Homo rudolfensis

It is estimated that Homo rudolfensis disappeared as a species around 1.8 million years ago. However, experts do not point to just one single reason why, but instead, the cause was likely a combination of different factors.

First is their inability to adapt fast enough to the ever-changing environment. Climate change could have had fatal blows to Homo rudolfensis’ survival, leading to some of their natural habitats being completely destroyed, or reducing their capacity to support a healthy population.

This scenario would have forced the Homo rudolfensis to be separated and fragmented, resulting in the second factor in their path to extinction, which could be genetic problems from isolation. A small population meant they would be more vulnerable to biological and environmental challenges like diseases and disasters because of the lack of diversity in their gene pool.

The third factor is the presence of other hominins that could be more adaptable and just an overall stronger survivalist than they are. Homo rudolfensis may have needed to compete for resources and territory with species like Homo erectus, which were believed to have modern-like body proportions and are thought to be better hunters and gatherers, because of their ability to travel long distances and utilize persistence hunting.

All these factors combined to create a perfect storm of challenges that Homo rudolfensis was not able to overcome. However, even though they may have already gone extinct, the fact that they almost existed more than twice as long as the modern human species, from 2.5 million to 1.8 million years ago, is still an incredible accomplishment as a species.

Author's Final Thoughts

Homo rudolfensis’ discovery gives us a window to the past, and a vision to infer how our ancient relatives and ancestors could have lived their lives. They survived in a harsh environment and circumstances for nearly 700,000 years. They likely faced climate changes, competition with more advanced human species, and habitat shifts that may have been too much to overcome.

Though they are already gone, studying this species helped us understand how early humans thrived and why some of them could not. Their existence and ultimately, their extinction, remind us that survival in the past required more than just strength and the ability to find a wide range of resources, but it also required adaptation, flexibility, competitiveness, and also sometimes a bit of luck.

Read next: Why Did Humans Begin Singing and Making Music Over 40,000 Years Ago? — Here’s What Researchers Think

References & Further Reading

Leakey, M. G., et al. (2012). New fossils from Koobi Fora in northern Kenya confirm taxonomic diversity in early Homo. Nature. https://doi.org/10.1038/nature11322

Antón, S. C., Potts, R., & Aiello, L. C. (2014). Evolution of early Homo: An integrated biological perspective. Science. https://doi.org/10.1126/science.1236828

Joordens, J. C. A., et al. (2013). Improved age control on early Homo fossils from the upper Burgi Member at Koobi Fora, Kenya. Journal of Human Evolution. https://doi.org/10.1016/j.jhevol.2013.09.002

Maslin, M. A., et al. (2014). East African climate pulses and early human evolution. Quaternary Science Reviews. https://doi.org/10.1016/j.quascirev.2014.06.012

Smithsonian Institution. (2024). Homo rudolfensis. Smithsonian National Museum of Natural History—Human Origins Program. https://humanorigins.si.edu/evidence/human-fossils/species/homo-rudolfensis