In the 'former' genus of skink called Mabuya (it was split into 4 sort of accepted genera) I've been told a whole group of them (Eutropis) which contains my gold skinks (aka sun skink) lose toes very easily...and they don't seem to care. Nobody knows why it happens and it doesn't seem to hamp the high flying skinks, who climb primarily by jumping (if they choose to climb) instead of using claws. How easily are they lost? Well, of those that I have had survive past 3 months in my care or a friends', (both of them dying recently for no reason at all, Gibber and Peeps), both ended up with one or less toes on the front limbs and none in the back limbs, with no cause whatsoever. Weirdly enough, it has taken my female until this summer, so 4 years now, to lose BOTH of her pointer fingers. Strangely enough, the bone actually DIED in that instance and had to be physically removed, by me, and she didn't actually flinch or move! They just don't seem to care, as observed with my male skink, who has a 90 degree bend in one of his terminal phalanges, which is going to fall off, and hasn't done anything about it. It only seems to happen to those of age adult or subadult (so about 1.5 years and up), as none of my juvi's aged newborn to 3 months old have lost them...they have all died or been sold off (only to die elsewhere) at that age. The amazingness of the Mabuya genus will one day conquer the world.