ok this sounds perfectly logical, but I just have *one* problem, how'd they get so big? wouldn't they be like human-sized when in anthropological form? And then like miniature car-sized when they're vehicles?
because the mother of all these things had great super amazing mammary glands that produced a milk that was like castro gtx for this things and made them grow big and strong.
ahh. ok. It all makes sense now. thank you, i like birds.