The Pokedex entries for Maushold are hilarious.
>they're gender unknown, not just because they're several individuals, but because people legitimately don't know what they are
>they act like a family unit, so it's assumed the big ones are mates, but nobody can confirm which is what, if they are mates at all
>the children are likewise assumed to be offspring but it's not clear
>nobody has actually seen Maushold reproduce, the little ones just appear out of nowhere
>even in gameplay, they don't actually evolve as far as you can see, Tandemaus just changes when you check it in the menu
For all know, these things are just a small colony of asexual creatures reproducing through budding.