1. Dirty cage: Gerbils are naturally clean animals, but if their cage is not cleaned regularly, it can start to smell. Make sure to spot-clean the cage daily and do a full clean once a week.
2. Wet bedding: Gerbils like to burrow in their bedding, and if it gets wet, it can start to smell. Change the bedding regularly, especially if it gets wet.
3. Dirty water bottle: Gerbils drink a lot of water, so it's important to keep their water bottle clean. Rinse it out daily and fill it with fresh water.
4. Gerbils: Gerbils themselves have a natural musky odor, which is mostly produced by their urine and droppings. This odor can become more noticeable if the gerbils are not cleaned regularly or if their cage is not well-ventilated.
If you're still having trouble with the smell, you can try using a deodorizing spray or powder in the cage. However, be sure to choose a product that is safe for gerbils.