You have to be built just so to walk on two legs. Bipedal animals -- those that walk upright -- have a center of gravity close to their hips. Their upper leg bones fit onto the end of the lower leg bone -- on humans, the hinge-like joint created there is called the knee. The result is an energy-efficient posture that allows the bones -- not just muscles -- to help support the weight of a bipedal animal. The first such animal might have been Eudibamus cursoris -- a lizard that flourished briefly about 290 million years ago. It might have run on two feet as a means of escaping larger carnivorous predators. Eudibamus probably died out 80 million years ago -- before there were dinosaurs that could walk on two legs. Scientists think the first mammal that walked upright was the ape-like australopithecines -- believed by scientists to be an ancestor of early humans -- which lived about five million years ago in Africa. Fossils of our human ancestors suggest that the ability to walk upright was an important development. It freed the arms to be used for other purposes -- long before a large, complex brain set hominids apart from other creatures.
if you mean walking, it was first discovered by apes. it is when they discovered how to walk that they started to evolve into humans today.
upright position
hominds stood upright and had a larger brain capacity than the apes and monkeys
Ardi is important because she is the oldest human skeleton in the whole world. She lived 4.4 million years ago. Ardi shows upright walking with a somewhat prehensilefoot, but no "knuckle walking" like the Great Apes.
if you mean walking, it was first discovered by apes. it is when they discovered how to walk that they started to evolve into humans today.
The only non-human primates without a tail are the great apes and regular apes such as gibbons . Of them the only one that walks upright all of the time is a Human. So the answer to your question is a Human. The other great apes can walk upright, but they do so only for short periods of time when needed.
Some key differences between human and ape skeletons include the shape of the pelvis (humans have a bowl-shaped pelvis for bipedal walking, while apes have a flatter pelvis for quadrupedal movement), the position of the foramen magnum (the large opening on the skull where the spinal cord enters; it is positioned more centrally in humans for upright posture), and the curvature of the spine (humans have an S-shaped spine for walking upright, while apes have a C-shaped spine for quadrupedal movement).
Fear of standing or walking upright
Australopithecus could walk upright on two legs.
Mary Leakey's discovery of footprints at Laetoli in Tanzania indicated that hominids were walking upright on two feet around 3.6 million years ago. This finding suggested that bipedalism evolved before the use of tools, changing our understanding of human evolution.
Walking upright.
Humans evolved from apes. So Apes came first.