Otherwise they won't breed, unlike other gerbil species, when the tank is too crowdy, no pups will be born at all. Persian jirds can reach an age of 6-7 years. Picture by Wim Duran. The most important thing is the space you give your Persian jirds. If they have less space they won't reproduce.
Persian jirds are very peaceful, fights almost never occur.
These jirds are excellent climbers and jumpers, thus need enough space and material to climb and jump on and off. Almost like a cat. As bedding you can use wood shavings or corn cob bedding, they don't need sand. Make sure you give them a nest box. Some hay or tissues serves as nesting material.