Mayhaps the flood was to wipe the DNAsaurs from the earth along with the dna corrupted peoples.
Fast forward to Moses going into Canaan land and the spies telling him they were Grasshoppers in their eyes. What many miss there is the statement that they devoured their inhabitants. They are said to have 6 fingers and toes and be 9-13 ft tall. These are fallen angels with human DNA mixed that the women would carry into the world. Now fast forward to Saul as king of Israel being told to kill everything with breath in certain cities. That means cats, dogs, horses, cattle, beasts, women and children? Why? because they altered each one for their own use. God hates them and wants them dead.In the Septuagint, Nimrod was the first Giant after the Flood. He was a hunter of men. Could this be a clue why God hated Esau and loved Jacon? Esau was a hunter and Rabbi's speak of Esau killing Cain in their writings. There are fables about Adam's animal skin was passed on to Cain and Esau killed Cain to get it because it had power from God. God made animals to reproduce after their own kind. If a man has sex with a goat, there won't be a half goat/man result, but the Nephilim could edit DNA to make a horse/human combo if needed. There is substantial depictions of these combo's in ancient archeology.
The point is God didn't make the dino's, He killed them. If they were wanted by God, the Ark would have been much bigger. There is absolutely no proof that the earth is over 6000 years old. The dino's drowned and are buried under feet of mud to fossilize them.
I believe that is EXACTLY the reason for the Flood, to wipe out the Nephilim, and the horrible genetically manipulated monsters they were able to create.