Not naturally. By instinct they wash and groom each other, and the person whose fault it would be if they were smelly would be the owner's. because they didn't clean the cage.
The future tense of "stink" is "will stink."
Other gerbils.
Gerbils are an animal and can not be "invented".
Male gerbils can be neutered, but it is not recomended. Female gerbils should not be spayed. In general male gerbils should not be neutered unless there is a good reason for it.
no gerbils are not originally from the UK but instead from the deserts of Asia. But you can still buy gerbils in the UK
Yes, mice are smaller than gerbils, but I think gerbils are the right size.
Barely. After a while, maybe about a month, the smell will start and you should clean the cage. They also don't pee that much because they are desert animals and therefore do not need much water. So it doesn't smell at first but eventually it will stink
They do have seizures (this is common in young gerbils)
No, they are not related. Gerbils are rodents, Rabbits are not.
No, Gerbils are vegetarian.
Gerbils and nothing else.
Yes, e.g Mongolian Gerbils.