We went away for 10 days and left our gerbil with a gerbil-experienced sitter. Upon his return to us, he refuses to chew on any of his favorite toys, like a willow ball or toilet paper roll; in the past, he attacked these voraciously. Can a gerbil’s teeth grow too long in 10 days? He had all his treats and toys left in his cage while we were gone, which I never do. I use them only for rewarded training. Did this give him an overload of toys? Should we take away his treats and chews for a few days or seek a veterinarian regarding his teeth?
Yes, sometimes a gerbil can get overwhelmed by too much in the cage. It is a good idea to take his toys out and give him one at a time to play with. After several hours without all those toys, offer him a toilet tissue roll or half a paper towel roll. He should immediately settle down to chewing it up. If he does not, I would be concerned like you are that the teeth are overgrown.
If a tooth is misaligned, too long, missing, etc. and the gerbil cannot gnaw, the teeth will grow quite a bit in 10 days time. If he will let you flip him over to check, you could see how his teeth look. Healthy gerbil teeth are yellow or orange. They are not white! White means calcium deficiency. There should be two long (same-sized) front top and two front (same-sized) bottom teeth, not so long that the gerbil cannot close his mouth comfortably.
If you are concerned, call your veterinarian to see about getting the teeth checked and clipped, if necessary. The expense for teeth clipping is usually not too much if done by a veterinary technician. It takes just a minute to do.