Join Date: Jan 2012
Location: Plattsmouth, NE
Hm, I wouldn't characterize leopard gecko females as enjoying one another's company. Most of them will tolerate another female, but they can still be competitive. Some individuals won't tolerate one another. Very few reptiles will choose company.
(Some snakes will do so for winter brumation, and garter snakes seem to do relatively well with the company of their own kind, for example. Sliders will stack up for basking, but won't really hang out together outside of that situation. Monkey-tailed skinks have complex social structures, pair-bond, and even provided limited parental care, making them very unique).
In most cases, reptiles prefer to be alone, and thrive better when kept alone. In this case, I would say that the slightly smaller animal is at a significant disadvantage, and the older animal is too aggressive to be a suitable cage-mate. They should be separated before someone loses a tail, toe, or eye.