How Did Australopithecus Survive in Africa for Nearly 2 Million Years Before Going Extinct? — Here’s What Researchers Discovered

Australopithecus is a genus of early human ancestors who lived in Africa millions of years ago. It is estimated that they first appeared around 4.2 million years ago and became extinct around 2 million years ago. Within that overall timeframe, different species in their group existed and survived for various lengths.

A popular fossil named Lucy is one of the best examples. She was classified as an Australopithecus afarensis. It is one of the most important hominin fossils found, as she has about 40% of her skeleton intact, which was a very high percentage for an ancient hominin fossil. It allows scientists to create a model of what she could have looked like anatomically.

It gave them an idea about how she and her kind could have possibly lived, and how they could have survived as a genus for nearly 2 million years. So in this article, let’s dive deeper into these ancient human ancestors, the Australopithecus

Upright Walking and Mixed Locomotion

One of the biggest advantages of Australopithecus was their ability to stand upright, and walk with two legs or bipedal. This is especially a significant skill in open grassland habitats, which were common in Africa during that time. It helped them move across the ground more efficiently, and it was also helpful in looking over the tall grasses to be aware of predators or spot possible food sources.

Bipedalism also freed their hands, allowing Australopithecus to use them for gathering resources and even possibly creating basic stone tools. There was an archaeological site in Ethiopia that was dated back to 3.4 million years ago, which was a time when Australopithecus were the only known hominin present in the area, where they found animal bones with cut marks. It is an indication that they were processed or butchered with a sharpened stone.

But Australopithecus were not fully human in terms of their movement either. They have learned how to walk bipedally, but they still retain some of their tree-climbing skills. Their fossils show that their arms and shoulders could still make them good climbers. So, this mixture of walking upright and climbing may have helped the Australopithecus survive in different ways.

In other words, they could have been a flexible group that could live either in trees or on the ground, possibly a mix of both. Depending on the environment in which they could thrive, Australopithecus climbed in forested areas or walked in open grounds. A versatility that helped them survive in a changing world.

Read more: Natural History Museum

Diverse Diet and Food Flexibility

Australopithecus: From Ape to Ancestor | Prehistoric Humans Documentary

Australopithecus was not as flexible as later hominins when it came to their diet, but they did still have diverse food options. They most likely did not eat as much meat as homo genus species; however, their plant diet included a wide range of sources such as fruits, possibly underground roots, and other tougher plant foods.

So, their diet was still mostly plant-based, and their survival relied heavily on vegetation rather than hunting animals. It is also apparent in their stature as they stand about 1.2 to 1.4 meters or 3 ft 11 in to 4 ft 7 in tall. So, they are likely slow, had small brains, and were not strong enough yet to be a predator.

Despite being able to walk upright, the ability to run long distances, which is crucial for persistence hunting, had not yet evolved in these species. Although there is some evidence that they could have butchered animal meat, their tool use and ability to make them is believed to be almost non-existent, or at least not to the level of a species capable of developing hunting strategies. In simpler words, they are most likely prey in the African environment, rather than the apex predators like later hominins.

Use of Trees, Shelters, and Predator Avoidance

So, if they are still prey, then how did they survive predatory attacks for nearly 2 million years? One of the first clues was their discussed flexibility above. They are capable of walking on the ground, but at the same time, they are probably still good climbers. It means that Australopithecus may have used tree covers and shelters above to avoid the ground predators.

There are also fossil sites where their remains were found inside caves or near them. This could mean that they used them for shelter against predators, but also the harsh weather. So, this mixture of two different locomotions is probably what significantly helped them survive for that long.

The fact that Australopithecus survived for nearly 2 million years speaks volumes to their dual-locomotion strategy. It allows them to get resources and avoid predatory threats in both forested and open environments. This is a flexibility that fully arboreal or terrestrial creatures do not possess.

Read more: Smithsonian

Coping with Climate and Habitat Change

Life And Death 3,000,000 Years Ago

Over millions of years of existence in Africa, Australopithecus likely faced different climates and environmental shifts like droughts or glacial periods. This could have been the main cause of some of the Australopithecus species’ extinction, but still, a few survived for a long time. A great example would be Lucy’s species, which is Australopithecus afarensis, which was believed to have existed for around 900,000 years.

They are adaptable to different environments because of their dual locomotion strategy. So, if one habitat loses its resources to maintain a population, Australopithecus likely moved and followed food and water sources. Some settings they could have lived in include woodlands, open savannas, and mixed forest environments. By being able to relocate to multiple different types of habitats, they were capable of escaping the droughts and resource scarcity.

However, soon the homo genus species arrived, like Homo habilis and Homo erectus, and the competition, combined with extreme climate and environmental fluctuations, may have pushed Australopithecus near extinction. These newer hominins were far more adaptable and just stronger survivalist overall because of their even more flexible diets, larger brains, stronger bodies, and tool use. So, Australopithecus numbers probably declined until they couldn’t adapt and compete fast enough anymore.

Author's Final Thoughts

The dual locomotion strategy of Australopithecus was key to their survival. It helped them exist for nearly 2 million years. They are capable of walking upright, but they still retain their climbing skills. Their largely plant-based diet was still diverse and flexible, and they were able to use shelter. They could also change habitats because of these traits, and it helped them weather the storm of climate and environmental fluctuations.

However, more pressure and challenges arose. Eventually, newer hominin species arrived. These creatures, like Homo habilis and later Homo erectus, were both more adaptable than Australopithecus. They had larger brains, stronger bodies, could use tools better, and even started to hunt other animals.

Combine this phenomenon with intensifying climate changes, and the traits that may have helped Australopithecus survive became less sufficient, and they soon met their end. But still, their legacy remains, and they could have paved the way for what would soon be the human lineage.

Read next: Why Did the Ancestors of Humans Lose Their Tails Around 20 to 25 Million Years Ago? — Here’s What Researchers Discovered

References & Further Reading

Stern, J. T. Jr. (1983). The locomotor anatomy of Australopithecus afarensis.Journal of Human Evolution.https://pubmed.ncbi.nlm.nih.gov/6405621/

Alemseged, Z., et al. (2010). Oldest evidence of stone tool use and meat-eating among human ancestors.Nature.https://www.mpg.de/research/oldest-evidence-human-stone-tool-use

Harcourt-Smith, W. E., & Aiello, L. C. (2004). Fossils, feet and the evolution of human bipedal locomotion.PMC / Philosophical Transactions B.https://pmc.ncbi.nlm.nih.gov/articles/PMC1571304/

Van der Merwe, N. J., et al. (2003). The carbon isotope ecology and diet of Australopithecus.Journal of Human Evolution.https://www.sciencedirect.com/science/article/abs/pii/S0047248403000502

Ward, C. V. (2013). Postural and locomotor adaptations of Australopithecus. In Evolution of Human Anatomy (Springer). https://link.springer.com/chapter/10.1007/978-94-007-5919-0_16