About 5 million years ago, in regions of East Africa, the environment began to change dramatically. Increasing drought caused the dense forests to shrink and vast savannas with tall grasses to spread across the landscape. Many animals that had previously lived in the trees were gradually forced to descend to the ground.
The new environment was dangerous. Large and fast carnivores dominated the savanna, while movement across open terrain required new survival strategies. Some groups of hominids managed not only to adapt, but also to gradually develop an upright posture, freeing their hands for carrying food, using objects, and interacting more effectively with their surroundings.
A less widely accepted scientific hypothesis, known as the “Aquatic Ape Theory,” suggests that some human ancestors lived near lakes or aquatic environments. According to this view, they spent much of their time in the water to protect themselves from predators and frequently fed on fish and other aquatic organisms.
Supporters of this theory argue that living in water may have contributed to the reduction of body hair, the development of a more upright posture, and other human characteristics. However, this theory has not been confirmed by most paleoanthropological evidence and remains controversial.
Most scientists believe that upright walking evolved primarily as an adaptation to the savanna environment. Standing upright allowed early hominids to see above the tall grasses, travel more efficiently across long distances, and reduce the body’s exposure to intense sunlight. At the same time, freeing the hands opened the way for carrying objects, using tools, and developing more complex behaviors.
The human spine gradually adapted to bipedal walking by developing its characteristic S-shaped curve, which provides balance and flexibility during movement. Through the process of natural selection, individuals with traits favorable for survival and adaptation had a greater chance of surviving and leaving offspring.
Thus, over countless generations, bipedal hominids walked more steadily, used their hands with increasing skill, and gradually developed more complex mental abilities — a long evolutionary journey that eventually led to the emergence of humans.
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