I read on a breeders site that they had one around 156g and they had a time line and they only lived for a few years. Do Giant leos have shorter lifespans?
I don't think anybody knows what happened to Moose, so it's hard to say. There's no indication that I've read anywhere that says giants have a shorter lifespan.
One breeder told me Moose was over-fed and over worked, but I have no idea if he was speculating or knows some inside story.