Dave Hone

But if you look at a lizard, particularly if you look at something like a crocodile, you see this massive, massive block of muscle sitting on the first third to half of the tail.

And that's what dinosaurs are doing.

It's the same thing as lizards and crocs.

They have this giant set of muscles on the first half of the tail.

That's anchoring on the femur, so the thigh bone on the back of that.

And muscles contract.

That's the one thing they do.

But now you've got a giant muscle.

And T-Rex, this muscle is like two and a half, three meters long.

It's going to be like this wide in the middle.

So when that contracts, the leg goes back.

foot stationary on the ground so the animal goes forward.

We do it with the butt.

So we're kind of weirdly how we organize our muscles.

But this is generally probably a better way of doing it.

Because you can get a really long muscle.

And of course, the longer the muscle, the more contraction you can have.

The hyper version of this is kangaroos.

So kangaroos supposedly get more efficient the faster they move.

They get so much energy return that when they're moving faster...