Subscribe Now! National Geographic Magazine $15
Visit our Online Shops

Sign up for free

Newsletters

Once a month
get new photos
and expert tips.

Madagascar Hissing Cockroach
Gromphadorhina portentosa

Photo: Madagascar hissing cockroach
A Madagascar hissing cockroach
Photograph by Roy Toft

Madagascar Hissing Cockroach Profile

This insect looks—and sounds—like anything but a run-of-the-mill roach. Madagascar hissing cockroaches are one of many fascinating animal species to hail from the island of Madagascar.

These cockroaches are shiny brown and oval-shaped, with no wings and a single pair of antennae. Males sport large horns, which give them an unusual and impressive appearance.

Males use their horns in aggressive encounters reminiscent of battles between horned or antlered mammals. 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.

Hissing is also part of the cockroach's mating ritual, and can be used as an effective alarm cry. Most insects that make noise do so by rubbing their body parts together or by employing vibrating membranes. Madagascar hissing cockroaches, however, exhale air through their breathing holes. This audible use of the respiratory system is far more common in vertebrates.

Like 99 percent of all cockroach species, Madagascar hissing cockroaches are not pests and do not inhabit human dwellings. These insects live on forest floors, where they hide amidst leaf litter, logs, and other detritus. At night, they become more active and scavenge for meals, feeding primarily on fruit or plant materials.

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.

Fast Facts

Type: Bug
Diet: Herbivore
Average lifespan in the wild: 2 to 5 years
Size: 2 to 3 inches (5 to 7.5 centimeters) long
Weight: Up to 0.8 oz (22.7 g)
Group name: Colony
Did you know? A small colony of hissing cockroaches can eat a large carrot in a single day.
Size relative to a paper clip:
Illustration of the animal's relative size

Multimedia

Bug Features

Photo: Dragonfly

Strange Love

Get a close-up view of the bizarre, sometimes painful, courtship rituals of dragonflies in this feature.

Other Large Bugs

Map: Locator map for the Madagascar hissing cockroach
 Madagascar Hissing Cockroach range

Special Advertising Sections

Photo: Horses and old barn

Enter Sweepstakes

Take a photographic journey through Montana and enter for a chance to win a trip for two!

Photo: Glass of water

Take Quiz

Eighteen percent of the world's population can't get safe drinking water. Test your water knowledge.

Bugs Right Rail

Get the Latest Headlines

Photo: Three-horned chameleon

Make us your online news source.

Get Animal Pictures

Photo: Honeybee on a flower

Get your daily dose of photos.

Bring Your Phone to Life

Image: Mobile phone and giraffe

Put the sights and sounds of National Geographic on your mobile phone.

For Kids!

Photo: A cartoon dog

It's no stretch to find fun facts on our Kids site!

Shop National Geographic DVDs

Photo: Human Footprint DVD cover

Whatever your interest, you'll be entertained and educated with our collection of best-selling DVDs.