Dave Hone

It means you're putting less energy in to walk because you're just getting a little bit of spring off every single step.

I mean, the big head makes it look more odd, but you look at dinosaurs as a whole and...

Over a third, probably 40, 45% is the group called theropods, which were all bipeds.

So T-Rex, Allosaurus, Velociraptor, Spinosaurus, many, many others that people may have heard of.

They're all bipeds built in this way.

There's a whole bunch of ancestral groups which are doing something very similar, including various crocodiles or...

relatives of crocodiles.

And then the birds are bipeds.

Birds are actually doing it in a much weirder way than theropods are.

The theropods are basically a lizard on its back legs.

I'm oversimplifying a lot.

I can hear paleontologists screaming as I've just said, it's a lizard standing up.

It's not a lizard standing up.

But they're doing a lot of the same stuff in the same way.

And that is really functionally about where you put muscles.

Because what you really want to do to walk forwards is you want to basically pull the leg back.

so that you're pushing the body off.

And the way they do that is the musculature on the tail.

So we don't have a tail, and indeed mammals that even do have a tail, you know, elephants and even lions, you know, it's a piddly little thing.

There's not a lot of muscle there.