It was one of the species that had been engineered by man. One of many like satyrs minotaurs, and other trans species creatures of old. That is why this world was washed.
The platypus looks to me like one of the very few that endured the flood. It looks like who ever designed it was having a laugh, or using up leftover parts. A poison duck beaver kangaroo bird. Just what kind of environment would it take to favor that kind of mutation? A lab?
Also the giraffe. why would God put those funny horns or whatever they are on the head of the giraffe unless he had a sense of humor? The giraffe must have been another gene splicing job by pre-flood man, that nevertheless survived. Maybe because of its long neck.
The unicorn = rhinoceros. behemoth = hippo. leviathan = crocodile.
Mammoths didn’t survive the warming of the earth following the end of the last Ice Age. Early man made cave drawings that included these creatures. But early man did not make any cave drawings of dinosaurs.
Upon the end of the Ice Age, the waters of the melting glaciers gathered into huge lakes, behind ice and earthen berms that the glaciers themselves formed as they pushed south. Upon a heavy rain, these dams burst, unleashing floods. We have lots of evidence of these floods.
Dinosaurs died a long, long time ago, before the start of ice ages. But, if they lasted had until the flood, they would have been on the Ark, because God put the animals onto Ark, not Noah. The flood doesn’t explain the disappearance of the dinosaurs or the unicorn or the disappearance of any other creature.
The funny thing about the flood is this: until recently, the naysayers said there was no flood. It was a flood myth, they said. But, the flood was never a myth. It has been verified by archeology and other means. The verification of the flood substitutes that the Bible is amazingly true.