Which is more probable?
1) It’s a stegosaurus, 155,000,000 years away from its normal time.
2) It’s an alligator, 700 miles from its normal range.
Three things occur to me about that petroglyph:
1. If the artist was painting an animal he was familiar with, how come he got the details so wrong? The plates are the wrong shape, and where are the tail spikes? Why does it have horns? You’d think a real live stegosaur would have made more of an impression.
2. At least some of those petroglyphs apparently postdate the arrival of Europeans—there’s a picture of a horse. How come no Europeans ever reported seeing a stegosaur, if they were still around?
3. Father Marquette, exploring the upper Mississippi in 1673, described “high rocks with hideous monsters painted on them and upon which the bravest Indian dare not look. They are as large as a calf, with claws and horns like a goat, their eyes are red, beard like a tiger’s and a face like a man’s. Their tails are so long that they pass over their bodies and between their legs under their bodies, ending like a fish’s tail. They are painted red, green and black...” Are we supposed to believe the Piasa Bird really existed too?