Bunny ears - the classic photobomb pose
of two fingers stretched out like rabbit's ears
behind another person's head
has been a popular prank for decades.
But it has a darker history.
Also known as "cuckold's horns", it goes back to the Middle Ages,
where the gesture was used to mock and shame a man
whose wife had cheated on him.
Cuckolds were sometimes made to wear antlers on their heads.
It's also said the gesture symbolised ass's ears,
a common insult in Medieval times.
The word cuckold comes from the French word for cuckoo,
a reference to that bird's habit of laying its eggs
in another bird's nest.
The cuckold was a figure of fun in the works of Chaucer and Shakespeare,
and he was still being mocked even in Victorian times.
We don't know who the first person was
to make the bunny ears joke in a photo.
Perhaps it began around the 1950s,
when people started taking photos of friends and family.
But, in any case, the idea caught on and spread.
In Italy, the gesture is made using the index and little finger
and is known as the "devil's horns", but the effect is the same.
Now it’s a common feature of selfie culture around the world.
But watch out, because you could be the bunny.