Dust bathing is when an animal rolls around in dust or sand, so that they can remove parasites from their fur, skin, or feathers. It is a maintenance behavior that is done by a number of different species of animal.
It has been suggested that wallowing (a behavior similar to dust bathing) may serve functions such as thermoregulation, providing a sunscreen, ectoparasite control, and scent-marking. (source)
Do gerbils need to take dust baths?
How often do gerbils need dust baths?
They need a dust bath at least once a week. This will mean that they regularly take a dust bath to get clean themselves of any parasites that get into their fur. But they need to have the option of taking more dust baths if they want to. This is why it should always be left out for them, and then the dust maintained and topped up when required. Just make sure to sieve it through every few days to get gerbil poop out.
How do you prepare a dust bath for a gerbil?
Sand can be purchased for a gerbil at any good pet store. However, use chinchilla sand for a dust bath. Don’t use normal sand or dust for a gerbil’s dust bath. The chinchilla sand can be kept in a clay sand tray for your gerbil. A clay sand tray will hold still rather than a plastic one which will move around the cage. If you have a lightweight tray, a gerbil will just wreck it. They will also not chew a clay tray.