i use the phrase that they can live up to 15 years.. yes there has been several gliders that have reached that number. as for avaerages... well like many animals the average life span is much shorter than the possible life span due to illness, and accidents, natural causes.. what I tell people is that it doesn't matter how long they are going to live, take the time you have with them, do the very best you can, learn as much as you can, and love them as much as you can, and the life you will have with your glider will be the gliders lifetime of quality