# How do you know $W$ and $Z$ bosons are really bosons and not fermions?

It has been always said that $W$ an $Z$ bosons are bosons and not fermions but is there any experimental trial that prove that? Has anyone put two of them in the same quantum state or studies have shown they obey Bose-Einstein statistics rather than Fermi-Dirac’s ?
It is really strange to me that such a short living particle been studied so.