A Rule Karl Marx Hasn't Heard Of

Mummy Bin Penguin has never heard of reversible dwarfing.

Nor is she curious.

But Terence and Baby Bin Penguin are.

What does that mean? says Baby Bin Penguin.

Ask him, says Terence.

But Gaius is turning away, his jocular remark having fallen flat, as quite often happens.

Follow him, says Baby Bin Penguin. Then come back and tell me the answer.

Terence follows Gaius, who has already caught up with Karl Marx.

I should have known better, says Gaius.

I fully agree, says Marx. Ice won't do it. Not in this weather.

Pardon? says Gaius. I was referring to Bergmann's Rule. No doubt you, as an intellectual of some standing, will have heard of it.

Terence is listening. He hopes Grandpa Marx will have heard of it.

Yes, of course, says Marx. It's wrong, is it?

No, says Gaius. Allow me to explain. These Bin Penguins are larger than life. Manufactured.

I have ascertained that much myself, says Marx.

And Bergmann's Rule being that species of larger size are found in colder environments, while smaller species are found in warmer regions.......says Gaius. You follow me?

Tasmania being a warmer region, says Marx.

Yes, says Gaius. Relative to the Antarctic where large Emperor Penguins are found.

Yes? says Marx. And these Bin Penguins?......I'm sorry, I'm not quite following....

Purport to be FAIRY PENGUINS, says Gaius. The small ones.

Baby Bin Penguin is small, says Terence.

Not that small, says Gaius. Only small for a bin. Not a penguin. Hence my joke, which fell flat predictably.

A joke, says Terence. So what was it?

Marx is glad Terence asked. He wasn't going to.

Hurrrrr, grumbles Gaius. It is tedious explaining a joke.

Please! Please! says Terence.

There is evidence that reversible dwarfing occurred during two relatively brief upward excursions in temperature, the Paleocene-Eocene thermal maximum, and the Eocene thermal maximum, says Gaius. I was merely observing.......

Ha ha, laughs Marx. You were suggesting the size of the Bin Penguins, in this moderate climate, indicates they are due for reversible dwarfing, but of course, being bins, the idea remains merely fanciful.

At least someone appreciates my sense of humour, says Gaius.

Terence runs back to Baby Bin Penguin.

It was a JOKE, says Terence. A stupid grown up one. You wouldn't get it.

Try me, says Baby Bin Penguin.

You remain fanciful, says Terence.

Fanciful! O how this delights Baby Bin Penguin.