Rats do indeed possess great intelligence, but these creatures may as well.

[There's not much chance ordinary hamsters could do the things Gundam's do, but in all likelihood he's just bred unusually smart hamsters.]

However, rats are used to living among their kin and possess loyalty. These fearsome beasts have not such a compromising nature. They fight cruelly, even among their own blood, and feel no remorse nor regret. Yet their loyalty can be earned even so...