>I haven't given him any fatty food, just the regular seed mix (Hagen) minus
all the sunflower seeds, and the nutri-blocks ("lab blocks"). They
sometimes do eat these. And I only leave enough in the cage to last from
one feeding time to the next
Those lab blocks are high fat, or seem to cause obesity in gerbils.
Between that and age, may be contributing to the weight gain.
There are medical things, such as progressive heart failure, or
kidney failure or diabetes, that can cause a gerbil to get fat. A
trip to the vet might be in order to rule some of those out.
Deb
Rebel's Rodent Ranch
