Madagascar hissing cockroach Gromphadorhina portentosa feeding on fruit. These cockroaches are native to the island of Madagascar off the coast of Africa and typically build nests in rotting logs. The hissing part of their name comes from the sound they make when alarmed. It is one of the largest cockroach species reaching 7.5 cm in length. Cockroaches like this aren磘 pests and serve important roles as decomposers, helping break down dead plant and animal matter and are an important food source to other animals.