"My lord! My lord! You left the fur off those mammoths!"
"I DID NO SUCH-- OH."
"It will never do, Lord. We'll have get rid of them."
"NONSENSE! WE'LL JUST PUT THEM SOMEWHERE ELSE AND CALL THEM, UM, ELEPHANTS."
"...Will that work?"
"I DON'T CARE, I'M NOT DOING THEM OVER."
Frankly, I think the idea that the gods got distracted while creating the world would explain a great deal.