I think the practice of walking for humans is both innate and developed social practice. For animals, the purpose of walking is just to move to certain places. Since they always have to conserve energy and avoid predators, all unnecessary movements could decrease their chance of survival. In other words, the end result of the walking is what really matters to the animals, not the process or method. However, humans in these days usually do not have to worry about the resources, so they can take their time to leisurely walk around, even if it is not the most productive thing to do at the moment. With the automobiles, people can easily get to far places quickly, which makes the practice of walking more voluntary and socially developed. Nevertheless, walking is good for the health; not only it helps our body to stay fit physically, but it also seems to produce some neurotransmitters such as dopamine that positively affect our brain. If walking is completely eliminated, it would likely cause both physical and mental illnesses, which is not ideal for our survival.