Dave Hone

It's about prey type.

Is it possible to know the sex of a T-Rex or any of the other dinosaurs?

Like what, what can paleontology show us?

So in theory, yes.

In practice, it's way more complicated.

So unless you get very lucky, we have a handful of specimens that still have eggs inside them.

Instant giveaway.

Um, but that's like two or three, um,

What you can look for is both reptiles and birds have a thing called medullary bone.

And when you're laying eggs and you need a lot of calcium very quickly, because that egg shell goes on basically like kind of like the last minute during egg development.

So you need a lot of calcium very quickly.

So during the laying season, these animals grow this really weird kind of bone texture on big things like the femur and the humerus, like really big bones in the body.

And it's got a weird texture because it's full of blood vessels.

And it's full of blood vessels so that you can basically apply a lot of blood supply to it quickly, suck up some of the calcium from that bone, take it through the system, put it on the eggs, lay your eggs.

We can find that.

So if you have a dinosaur bone and it's the right kind of thing, so you can't do it on like a finger or a claw or a bit of rib, but nice big bone, you could cut a chunk of that out.

grind it down to the point that it's virtually transparent, fraction of a millimetre thick, put it under a microscope and have a look.

And if you see the right bone texture, there's some exceptions, but that's very probably medullary bone and you have yourself a female.

So the instant assumption is, okay, so you can tell female from male.

No, we can tell laying female from everything else.