Rivals ram one another with their horns (or abdomens) and during the fight often unleash the amazing hisses that give the animal its name. Winning roaches hiss more than losers, so the sounds may be used to help determine a roach hierarchy.
The Madagascar hissing cockroach even begins its life in an unusual manner. Females create a cocoon-like egg case called an ootheca and carry their eggs (and neonatal nymphs) inside their bodies. They then bear living young - as many as 60 nymph roaches.