Gdans were predatory creatures that originated from the planet of Qiilura. Reaching a full size of approximately thirty centimeters, it required an entire group of them to successfully kill even a young merlie. Though they were small, they would still attack sapient beings, especially when they were in groups. They were not aggressive or dangerous during the day, but at night, when they came out of their burrows to hunt, the farmers in the area would lock up their homes and avoid the fields. The locals were not afraid of their teeth, but of the dangerous germs they carried; even a small cut or bite could cause death.
Living beneath the surface, gdans were very skilled at digging. They would create extensive tunnels that were large enough for sentients of human size to move through on their hands and knees, and Omega Squad, a clone commando team from the Galactic Republic, used this to their benefit during the Mission to Qiilura. Gdans also dug out spacious chambers, big enough for a clone commando to stand upright, providing them a place to escape from rising water after rainfall. Omega Squad observed small ledges on the tunnel walls that the gdans used as shelter.