text: The answer is found in Genesis as to how it was done:\n\nGenesis 6:19-22\n\nAnd of every living thing of all flesh,two of every sort shalt thou bring into the ark,to keep them alive with thee;\nthey shall be male and female.Of fowls after their kind,\nand of cattle after their kind, of every creeping thing of the earth after his kind,two of every sort shall come unto thee, to keep them alive.\nAnd take thou unto thee of all food that is eaten,     and thou shalt gather it to thee;and it shall be for food for thee, and for them. Thus did Noah; according to all that God commanded him,so did he.\n\nThe key phrase being: two of every sort shall come unto thee - meaning the animals where led to Noah by God. \n\nCome to consider it, the animals knew of the flood by their senses (even today animals know of impending danger even before it happens) and the animals moved to higher ground of which the ark was located.\n\nFurthermore:\n\nAlthough we do not know the exact length of a cubit at this time (verse 15), later, it was about 18 inches making the ark 450 feet long, 75 feet broad and 45 feet high, with a displacement of 14,000 tons its carrying capacity equalled that of 522 standard railroad stock cars (each of which can hold 240 sheep). Only 188 cars would be required to hold 45,000 sheep-sized animals, leaving three trains of 104 cars each for food, Noah's family, and 'range' for the animals. Today it is estimated that there are 17,600 species of animals, making 45,000 a likely approximation of the number Noah might have taken into the ark."