I have been researching blue tongue skinks, and found they come in all sizes and morphs, not as many as snakes but they do vary. Their pluses are they are pretty friendly and easy to handle, are not picky eaters and have live births. I am considering a pair myself. If you watch some of the u-tube videos there is one that will give you the name of skinks that actually need more then one in a tank, cause they prefur a social group. Some skinks stay only 10 inches while the great northern gets 18-22 inches. Hope this helped, Good luck.