Why Humans Became Bipedal

There have been many theories about why humans became bipedal, and even more were made due to the fact that early hominins started walking straight up on two feet before the significant grow of their brains, which was originally thought to be the cause of bipedality. According to one of those theories which was made by Owen Lovejoy, early hominins started walking up right so that their hands could be freed and they could carry food in them. In this way, a male hominin could bring "home" much more food for the female and youth hominins. This could also be used to impress the female hominins and to allow the males to reproduce and pass there genes on to another generation, ensuring the survival of their species.
Another theory is that the early hominins that used to live in the savanna needed to walk upright so that they would become taller and so that they would be able to see over the tall grass which could be found commonly in the savanna. The main problem with this theory is that other evidence suggests that the early hominins started their bipedalism in the forests, not in the savanna.
Another theory is that early hominins started to walk on two feet as it was more energy efficient and therefore allowed them to travel greater distances when following their prey. It has been proven that humans walking on two feet use up less energy than chimpanzees walking on all four feet. This theory was suggested wrong when chimpanzees used in a test used more energy while walking on just two feet than when they walked on all four feet. These chimpanzees were being observed though and it was proven that they use big muscles to make small steps while humans use small muscles to make big steps.