Human beings are known for gaining weight as they grow taller, but the growth pattern of homo sapiens took a weird turn around 1.5 million years ago. They started losing weight and growing tall. Researchers at the Cambridge's Department of Archaeology came to this conclusion after analyzing 311 specimens of upright walking hominids.
According to the researchers, at one point in time, humans suddenly gained 4 inches, thereby becoming more taller and slender than their predecessors. Researchers believe that this change was a response of the human body to the new conditions. The report of this study is published in the current edition of Royal Society Open Science.
Reason behind this abnormal structure
The researchers who took part in this study believe that this change in the growth pattern of human beings happened as a result of their adaptation to the new environment.
"An increase solely in stature would have created a leaner physique, with long legs and narrow hips and shoulders. This may have been an adaptation to new environments and endurance hunting, as early Homo species left the forests and moved on to more arid African savannas," said lead author Manuel Will, Phys.org reports.
During the study, researchers analyzed hominid bones as old as 4.4 million years ago, and as recent as the bones of modern men. Most of the human history included people with consistent body sizes, but at one point in time, the height was considerably increased due to the necessity to meet environmental needs.
Humans became more tall and slim as they moved from the forests to the arid African savannas. Being tall and lean allowed human beings to see further over the savanna, and it also helped them to run fast during the time of hunting.
The ability to run longer distance
Deers were the most favorite prey of humans during the ancient ages. But for a normal human, it is practically impossible to chase down and hunt down a deer as they run faster than a man. To resolve this problem, humans adopted a new method of hunting called 'persistence hunting'. In this peculiar way of catching prey, humans used to chase the prey until it gets exhausted. Being tall and lean allowed humans to run long distances, and thus they easily exhausted their preys.
Being lean also allowed humans to retain less heat in their body. Humans have less hair on the body, and thus they can easily cool down by sweating, while other animals can't. A million years after the growth spurt, humans gained more than 20 pounds, as they moved to a colder climate. Gaining weight helped humans to store insulating fat in the body, a trick to adapt to the new environmental conditions.
Astronauts get taller in space
Earlier, NASA scientists have revealed that astronauts gained height by three percent while they stay in microgravity space. This finding also indicates the peculiar nature of the human body to adapt to their current living conditions. In microgravity conditions, human spine gets elongated, enabling them to adjust to space conditions better. Interestingly, the height gained by humans during their time in space will get shortened after they live on Earth for three or four months. Something that may spur more research in height-gaining for humans in the future.
