The basic inspiration and expiration process of the roach sounds simplistic, but the roach has more complex ways of controlling its respiration. Roaches don't breathe non-stop. In humans, for example, the cycle of bringing in oxygen and expelling carbon dioxide is continuous; it does not stop even when we sleep. In roaches, however, all of the spiracles can close down causing discontinuous ventilation. Additionally, a 2009 study published in the Journal of Experimental Biology found roaches kept their spiracles closed for longer periods when their environment was drier. Lead scientist Dr. Craig White believes this increased period of closure allows the roach to keep more of its own moisture locked in; roaches can dehydrate in a week without water.