"Two twins"

[PGmicstand]

Just why? Was visiting an animal park recently and the person demonstrating/showcasing the animals said that the lemur family was "Dad, mu., big brother, two twins, and little sister. "
Twins IS two. Two twins suggests to me two lots of twins, so four individuals (although to properly ramp up the pedantry that would correctly be two sets of twins).
I see it on MN a lot too.

Twins are not always together though. You can have "one twin".

Yes, I don’t necessarily think that’s unreasonable in the context of animal husbandry. I’ve certainly heard it used often in lambing, where both twins don’t necessarily survive, or the punier one might need separate care/feeding.

Maybe they weren't twins with each other? Maybe a stupid person wrote the sign?

Just re read that they were speaking, maybe it was one of those things that come out of your mouth and you cringe about later?

In this case, where one animal didn't survive, surely the correct form is "x was a twin but their sibling didn't survive."?
In this case both animals were bouncing around quite happily.

If the animal keeper had been saying the names - e.g., "A is the mother, B is the father....and E and F are twins..etc." that would be fine.

It's the specific wording of "two twins" that I take exception to, as its unnecessary to quantify how many 'twins' means.

Do you object to the use of "one twin" to refer to, well, one of the twins?
If you do, please explain why...
If not, how can you object to "two twins" to refer to both of the twins?

Depends on the context. Saying one of the twins has a tattoo for example, fine.
But twins doesn't need quantifying by 'two'. So, one twin has a tattoo, or both twins have tattoos, or maybe neither of the twins do.

One twin meaning the word "one" is giving additional information to quantify why you don't say "twins" because twins means two.

So, one twin has a tattoo, or both twins have tattoos, or maybe neither of the twins do.

Please tell me the hypothetical twins getting tattoos aren't lemurs.

In neonatology we would usually refer to surviving twin. Because having been a twin is not the same as having been born a singleton, even when only one baby survives. This may well also be true for lemurs.

Not to my knowledge but who knows what goes on at the zoo after hours when the drinks are flowing?