WHEN DID HUMANS BEGIN WALKING UPRIGHT?
The human species, or Homo sapiens, belongs to the hominid family tree. Hominid means “human types,” and describes early creatures who split off from the apes and took to walking upright or on their hind legs. The reasons that human ancestors started to walk upright are not known. Scientists believe it may have been a response to environmental changes: as tropical forests were beginning to shrink, walking might have been a better way to cross the grasslands to get to nearby patches of forest for food. Standing upright also may have been a means of defense that slowly evolved. By standing upright, animals appear bigger and more impressive in size than they normally are. In addition, the ability to stand up and get a wider view of the surroundings gives an animal an advantage in the tall grasses. Walking upright also frees up the hands to carry objects, such as tools. The oldest known humanlike animals to have walked upright are believed to be Australopithecus afarensis, meaning the sout
