Leave out food and water. If you have wooden/tiled/laminate floors, put flour on it (You can see foot prints) get down on the floor and look at the world like gerbil. look in dark places. I don't know much about gerbils, but go look in places that would be attractive to them.
Do they respond to their names? if so, call them.
Do they make noises like guinea pigs? if they do, keep everything quiet and listen hard.
Do they respond to their names? if so, call them.
Do they make noises like guinea pigs? if they do, keep everything quiet and listen hard.