Domesticating animals follows when a civilization applies agriculture because it helps in plowing hard soil. Farm animals are also a good source of edible meat, milk and eggs. An acre of land can therefore feed more herders and farmers as much as 10 to 100 times as what the hunter gatherers can gather in a same sized area. In ancient times, these meant more surviving people and thus a military advantage that agricultural tribes had.
Another advantage of agriculture is that it enables agricultural people to have higher birthrate than the hunter-gatherers. Mothers of hunter-gatherers society are capable of carrying only one child at a time. And so, mothers of these societies need to lengthen the time of the next birth of a child until the infant is able to walk. Agricultural people on the other hand need to stay close to their farms. They are not burdened with the problems of constant traveling and so are able to have as much children as they want. Higher birthrate and the ability to produce food enable agricultural people to have higher population densities than the hunter-gatherers.
A settled existence for the agricultural people enables them to develop a skill for storing food. Unlike the hunter-gatherers, food lasts for a short time because they are not able to protect them if they are to store them at some place.