Gerbils that are kept in captive environments can develop a behaviour known as ‘Bar Rub’. This is where they continuously chew on the bars, sometimes so much that they can give themselves little sores around the mouth and rub away their hair. If the bar rub is very bad, then the gerbil’s teeth can become misaligned, which may prevent them from eating.
If your gerbil gnawing the bars of its cage, you'll need to intervene
There are lots of different reasons that gerbils chew the bars - check out our Gerbil Chewing Bars page for more information.