In the original story of Noah and the ark, the billions upon billions of rotting and bloated human and animal carcasses floating in the sea are never mentioned. Do you believe that ignoring this grim fact was a marketing decision? Do you think it would have been just too expensive to include a large number of plastic animals, with an X over each eye, for each of the millions of Noah's Ark bath toys?
We now know that telling species apart can sometimes be fiendishly difficult, and it is often only possible through DNA testing—which was only invented in the 1980s, and so was about five thousand years too late to do Noah much good (unless, in addition to building wallaby traps, Noah also built a time machine and could therefore travel into the future—and why should he not, as it doesn't make the story any more incredible). Biologists are forever lumping creatures together when they find some that actually belong to the same species, or more often, splitting species apart when it becomes evident that although two creatures may look alike, they don't belong to the same species at all. In addition to this inconvenient fact, there also exist long chains of a single species, but the species gradually morphs so that, when the two ends of the chain meet up, the creatures at the beginning and end of the chain no longer belong to the same species! This is called a ring species, and it gives taxonomists, who are the people whose business it is to classify animals, one big collective pain in the Equus asinus.
In light of this complexity, do you now believe that it is obvious that Noah didn't tell the animal species apart because, in actual fact, he didn't have to? Is this because God must have magnetized the animals that he wanted to survive, and so they were attracted to the ark by a powerful force? Do you now believe, as I do, that this force was so powerful that it made all of the animals fly through the air at top speed, sometimes hitting the ark with a thunk and a disappointing splat? Does it make you happy, as it does me, to imagine Noah, seeing yet another pair of bewildered animals speeding like missiles toward the ark, taking cover and yelling, “Elephants at six o'clock! Incoming! Incoming!”