The relationship between humans and ostriches is that of profit. Humans find profit in ostriches. Some people have lived using Ostrich for cultural needs and survival and that was seen throughout history. Racing one the back of Ostriches is a sport that still exists in many locations, sometimes they are being used similarly like horses since they are very intelligent. Humans also use Ostriches as a source of meat and eggs. Same for leather, it is one of the toughest leathers in the world and they seem to be taking good money turning Ostriches to leather.