It's been a long-winded debate over what exactly caused early humans to start walking upright back in ancient times, but a recent study suggest that the move towards bipedaling was due to the shift in geology, and rocky landscapes made it difficult to get around on four legs, thus the switch to two legs to get around quicker.
The study, which was published in this month's issue of the archaeological journal Antiquity, claims that the transition to walking upright was prompted by volcanoes and shifting tectonic plates in East and South Africa, which inevitably produced rocky terrain, making it more and more difficult to get around.
This encouraged early humans to improve their locomotor skills by implementing activities such as climbing and balancing over rough ground. These types of movements are better done upright, rather than on four legs, so after that initial transition, humankind has since been walking on two legs, as it provides better all around movement.
Previously, it was highly cited that climate change was the culprit for getting early hominids to walk upright. As the percentage of forests in Africa declined due to temperature fluctuations around 2.5 million years ago, early humans slowly made their down from trees and traveled on the ground instead, which can be done quite easily with two legs, rather than the four legs that are crucial for tree climbing (just as any kid).
Of course, there's no definitive proof to either argument, but rather mild evidence that supports the claims. Both theories make sense in their own ways, and it's possible we may never know the exact reason why us humans began walking upright. Think of it this way, though: What would the world be like now if we were still walking on four legs today?
IMAGE CREDIT: epSos .de