Wherever the move may have been made, in one or in several places, and whatever may have been the particular circumstances attending the domestication and early use of crop plants and animals, the case sums up to about the same result. Through long ages of work and play men (perhaps primarily women) learned the difficult and delicate crafts of husbandry and carried their mastery of these pursuits to such a degree of proficiency, and followed out the lead given by these callings with such effect, that by the (geologic) date of early neolithic times in Europe virtually all the species of domesticable animals in three continents had been brought in and had been bred into improved races.[37] At the same time the leading crop plants of the old world, those on whose yield the life of the Western peoples depends today, had been brought under cultivation, improved and specialised with such effect that all the advance that has been made in these respects since the early neolithic period is greatly less than what had been accomplished up to that time. By early neolithic times as counted in West Europe, or by the early bronze age as counted in western Asia, the leading domestic animals had been distributed, in domesticated and improved breeds, throughout central and western Asia and the inhabited regions of Europe and North Africa. The like is true for the main crop plants that now feed the occidental peoples, except that these, in domesticated and specialised breeds, were distributed through this entire cultural region at an appreciably earlier date,--earlier by some thousands of years.[38] In late modern times there have been added to the civilised world’s complement of crop plants a very large and important contingent whose domestication and development was worked out in America and the regions of the Pacific; though most of these belong in the low latitudes and are on that account less available to the Western culture than what has come down from the prehistoric cultures of the old world. These are also the work of the stone age, in large part no doubt dating back to palæolithic times.