Since cockroaches live underground or in small crevices, one hypothesis was that they might hold their breath because of the build-up of carbon dioxide in these small spaces. But a team of Australian biologists tested cockroach breathing patterns in different conditions, including high CO2, low CO2, as well as in high and low humidity. They discovered that cockroaches took shorter breaths and held their spiracles closed longer in dry conditions than in humid. They didn’t breathe less often in high CO2 than in low CO2 conditions. So The Cockroaches Can Conserve Water in Hot, Dry Conditions by Holding Their Breath? Exactly. This trick is probably one of the ways the lowly cockroach has managed to colonize and thrive in such diverse climates and environmental conditions.