80 million years ago
Long before people. Some dinosaurs were alive then. Elasmosaurus swam in the water while they walked on land.

Dinosaurs · Dinosaurs
It lived with the dinosaurs. It was not a dinosaur. Come and meet it.
Meet it
Say it like this. Ee-LAZ-mo-SOR-us. It means thin-plate lizard. The plates are in its hips.
Long before people. Some dinosaurs were alive then. Elasmosaurus swam in the water while they walked on land.
Almost as long as a school bus. Most of that was neck. About 23 feet of it.
You have seven. A giraffe has seven too. Elasmosaurus had 72 in a row. That is almost as many as any animal ever found.
Scientists call it a plesiosaur. It breathed air. It came up to the top to take a breath, then went back down.
Two in front and two in back. They worked like paddles. The head stayed small and the neck could curve.
In those days a shallow sea covered the middle of North America. The bones were found in Kansas, where that sea once was.
Try it
Slide to grow the neck. Start with the seven bones in your own neck. Stop when you reach Elasmosaurus.
That is your neck. Seven bones.
A true story
A doctor named Theophilus Turner found some huge bones in Kansas in 1867. He was an army doctor. He sent them east to a scientist in Philadelphia named Edward Cope.
Nobody had seen an animal like this. Cope studied the bones. He saw a long, long chain of them and he made a guess. He guessed it was the tail.
So he put the head on the end of the tail.
A year or two later another scientist, Joseph Leidy, looked at the drawing. He said it was backward. The long chain was the neck. Cope fixed it.
Even great scientists get things backward. What matters is that they check, and then they fix it.
Your turn
Grandpa Fenn has more doors.