True about they being jumpers. Buy there is no mouse or cat and it was in my study where floor is wooden and small area.Yoyo's are jumpers and can wriggle considerable distance before succumbing, I lost a prize one last week that jumped through a 1 - 2" gap where filtration pipes enter the tank, found it on the other side of the room, if these are cats or other animals around they can easily disappear.