Hawks, large birds, things like that that eat prarie dogs and gerbils.
yes, humans
humans and other wolves and maybe a bear
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.
They do have seizures (this is common in young gerbils)
No, Gerbils are vegetarian.
No, they are not related. Gerbils are rodents, Rabbits are not.
Gerbils and nothing else.
Yes, e.g Mongolian Gerbils.