So, I just got two gerbils on the 16th. They have a four story cage with clear plastic in the front, and so far, everything seemed pretty normal. I put a sand bath in for them to bathe in, and then took it out after they were done. However, after I removed the sand bath, one of my gerbils ran to the top of the cage and started scratching like crazy at the corners and floor of the cage. He sometimes stops and relaxes a bit, but then he runs back up and starts scratching again. Is this normal?

The next night, both of my gerbils started gnawing at the cage walls and scratching at the ground in the same two corners. I tried putting chew toys at the corners they scratch at, but they just find a way to move the toy so the can keep scratching. I've looked up a lot about gerbil behavior, and I know that digging is normal and natural. I can't help but wonder if all of this scratching and gnawing is normal, though.