Madagascar Hissing Cockroach

(Gromphadorhina portentosa)

Habitat and Distribution: Found among dry leaf litter in tropical lowland forests on the island of Madagascar (off the southeast coast of Africa).

Size: 2-4 inches

Wild Diet: Primarily rotting plants and fallen fruit; also small insects and carrion

Predators: Arachnids, small mammals, birds, snakes, lizards, frogs and larger insects

Reproduction: Madagascar hissing cockroaches breed year-round. Females produce and carry ootheca (egg cases) internally. After a 60-70 day gestation, the eggs hatch inside the female and 15-40 nymphs are born live. They are about as big as watermelon seeds. Nymphs molt six times before reaching adulthood, a process that takes 6-7 months. Parents stay with nymphs until they are able to fend for themselves.

Behavior: Madagascar hissing cockroaches are nocturnal and live in large colonies. They are excellent climbers and can even scale smooth vertical glass. They communicate with a variety of loud hissing sounds, produced by forcing air through abdominal breathing pores called spiracles. There are two types of hisses: a disturbance hiss and a fighting hiss. All of the roaches can make the disturbance hiss once they have completed their fourth molt. The males use the fighting hiss when they are challenged by other males. The males establish territories which they defend, but the females do not fight and can cross between the territories of several males.


IUCN Status: Not Evaluated

Wild populations are difficult to study because they are found only in Madagascar, a country in political turmoil with few passable roads. The natural forest required by these cockroaches (and many other species found only in Madagascar) is rapidly being fragmented and degraded.

Did you know?

  • Cockroaches are an important part of the forest ecosystem. They recycle dead and decaying plant and animal matter into nutrients that can be used by the plants in the forest.
  • Unlike most other cockroaches, Madagascar hissing cockroaches are wingless.
  • Males have horn-like projections on the thorax that are used during combat with other males.