Several cockroach species are considered giant. Of these, the most well known are the Madagascar hissing cockroaches and the rhinoceros cockroaches.
Madagascar hissing cockroaches (Gromphadorhina portentosa) are wingless and relatively slow moving. These nocturnal natives of Madagascar thrive on forest floors in rotting logs and feed on decaying organic matter. Hissing cockroaches grow up to over 7 cm in length from horn to antennae and can measure up to 2.5 cm wide. Unlike other species, the female hissing cockroach gives birth to live young. Males are aggressive and use their horns in combat with rival males. The hissing which characterizes this species is used in defense, mating, colony hierarchy and other communication.
Rhinoceros cockroaches(Macropanesthia rhinoceros), also known as giant burrowing cockroaches or litterbugs, are wingless, glossy, dark brown and stout-bodied. These cockroaches weigh more than 30 grams each and can exceed 8 centimeters in length. Native to Queensland, Australia, this species lives in deep burrows within the ground and consumes primarily dead leaves.
Most well-known cockroach pests measure less than 5 cm in length. American cockroaches (Periplaneta americana) are approximately 4 cm long as adults; German cockroaches (Blattella germanica) measure 1.6 cm in length as adults. Asian cockroach adults (Blattella asahinai) grow up to 1.6 cm in length, while Oriental cockroach adult females can be longer than 2.5 cm. Brown-banded cockroaches only grow to reach 1.3 cm in length, and smoky brown cockroaches grow up to 3.8 cm as adults.