My gerbil Button passed on today. I'm not entirely sure how long Gerbils live for, but we've had her about 2/3 years and she wasn't a baby when we got her.
She looked so peaceful snuggled up in her box we thought she was sleeping until we noticed she hadn't moved all day, and when we put our hands in the cage to stroke the top of her head she didn't stir.
She will be missed, not just by me and mum, but also by Lolli; our kitten who was her best friend.