by Tom Twardzik

Deep in the tropical forests and dense jungles of Madagascar, from a place hidden beneath damp leaf litter and loose tree bark on the forest floor, comes a loud, sharp hiss.

Below you, on the ground, the Madagascar hissing cockroach crawls through the evening darkness, searching for food among the detritus (fresh, fallen fruit or a leafy branch makes a good meal for these insects).

These giant cockroaches are fascinating examples of the adaptations that animals develop to survive and thrive in their natural environments. From its body and behavior to its communication and reproduction, it’s a unique and incredible insect.

Let’s delve into some amazing Madagascar hissing cockroach facts.

Biology of Madagascar Hissing Cockroaches

Size comparison of the Madagascar Hissing Cockroach vs the American Cockroach and the German Cockroach
Size comparison of a Madagascar hissing cockroach (middle) and two common house roaches

The Madagascar hissing cockroach, Gromphadorhina portentosa, is a nocturnal forest scavenger. It’s a member of the Blattodea order of insects but it’s quite different from those bugs in the much better-known Blattidae family—the American cockroach, German cockroach and others. While those species are now common around the world, the hissing cockroach has remained on its native island.

The Madagascar hissing cockroach is one of the largest cockroach species in the world, growing to 2–3 inches long as an adult—one could almost cover your palm from thumb to pinky—and weighing nearly 1 ounce. It’s shiny and oval-shaped, with one pair of long, hairy antennae extending from its head.

This insect is a sharp dresser. Its exoskeleton has a striking gradient color, fading from black at its head to light brown at the rear of its abdomen. It has black, spiny legs. Stripes of light brown or yellow cross its back like the pattern of an armadillo’s armor.

Close-up, side view illustration of the horns of a male Madagascar Hissing Cockroach
Horns of a male Madagascar hissing cockroach

The Madagascar hissing roach has a unique pair of large, horn-like bumps that protrude from its pronotum (the foremost section of a cockroach’s thorax, which sits directly behind the head). Males use these horns in battles for dominance, similar to the clashes between head-butting bighorn sheep.

Females are not at all aggressive toward other cockroaches and have no need for horns. They typically lack these bumps altogether or have very small, non-functional ones. Their antennae are also smoother. Females are social insects and commonly form groups within colonies.

Madagascar hissing cockroaches are flightless. While several other species of flightless cockroaches have wings, the hissing cockroach has no wings at all. Instead, its back is covered by a hard, wide exoskeleton that protects it from danger.

Though it can’t fly, it can scale smooth, vertical surfaces using special, sticky pads and tiny hooks on its feet. In the wild, it has no trouble scaling branches and tree trunks, navigating thick underbrush and climbing slick rocks.

The Hiss of the Madagascar Roach

Illustration of a Madagascar cockroach in a girl's palm with sound wave of hissing drawn above

Click to play a hissing cockroach sound

Communication via sound signals is common throughout the animal kingdom, from birds, snakes and frogs to meerkats, lions and whales. But among cockroaches, the Madagascar hissing species is unique. No other cockroach communicates audibly the way this species does.

True to its name, the hissing cockroach can send several specific messages via slightly different hissing sounds. These messages might be meant for friends, mates or predators.

How do hissing roaches hiss?

Illustration in closeup of Madagascar cockroach spiracles, used for breathing
The hissing cockroach hisses through holes in its body called spiracles.

Cockroaches and other insects breathe through tiny pores in their bodies. These openings are called spiracles and they’re located around a cockroach’s abdomen and thorax. As part of the insect’s respiratory system, spiracles take in oxygen and deliver it directly to muscle tissues.

The Madagascar hissing cockroach has a special pair of modified spiracles in its abdomen. By blowing air rapidly through these spiracles, it creates a loud hissing sound that can be quite startling to animals and people nearby.

This is much different from crickets, which rub their forewings together to produce chirping sounds, or frogs, which vibrate their vocal cords to produce their croaks. A Madagascar cockroach hisses in the same way a human would—by sharply exhaling its breath. Though not quite as loud as a cricket’s chirp, a cockroach’s hiss is audible from several yards away.

Why do hissing cockroaches hiss?

Madagascar hissing roaches produce several different types of hisses that they use to communicate with other cockroaches (and predators). They produce special hisses for aggressive encounters, mating rituals and emergency situations. Though it might be difficult for a human to understand the meaning of a cockroach’s hiss, these insects can understand each other and even differentiate between friendly hisses and aggressive hisses.

Males produce aggressive hisses during clashes with other males. They also hiss when trying to attract a female and during mating. Males use a long-range hiss to call to females and a short-range hiss to talk to roaches that are nearby.

If you come across a Madagascar hissing cockroach in the forest, you’ll probably hear its alarm hiss. This is the disturbance hiss that all roaches can produce—males, females and nymphs—and it’s their signal that danger is nearby. It sounds similar to a snake’s hiss, which is another reason it can be frightening to hear in the woods!

Life Cycle of the Madagascar Cockroach

Illustration of Madagascar Hissing Cockroach nymphs emerging from a female
Illustration of hissing cockroach nymphs emerging from a female

Madagascar hissing cockroaches are different from most cockroach species in that they’re ovoviviparousthey give birth to living young.

Most cockroach species produce egg cases called oothecae that contain a dozen or more eggs in each. They carry these oothecae temporarily and place them somewhere hidden shortly before it’s time for the eggs to hatch.

The female Madagascar hissing cockroach, on the other hand, carries its egg case within its body while the eggs develop. Then, they hatch inside the female and, as neonatal nymphs—baby cockroaches—they remain in her thorax for several weeks. A female can carry up to sixty nymphs at once!

The nymphs remain in the female’s body for as long as two months before they’re finally born. After birth, the newborn nymphs become independent, fending for and feeding themselves.

A cockroach nymph molts its old exoskeleton and grows a new one several times as it grows. Each phase of development is called an instar. On average, hissing cockroach nymphs go through six instars before they’re fully mature.

After it molts, cockroach nymphs sometimes appear white or very pale. They’re particularly vulnerable during this time because their new exoskeletons aren’t ready to protect them. The nymphs regain their color as the keratin (the protein that also forms hair, feathers and claws on other animals) that makes up their exoskeletons hardens. Sometimes, cockroaches eat their old exoskeletons to recycle the nutrients contained in them.

The hissing cockroach’s life cycle is a long one among Blattodea. The nymphal stage can take seven months, including the time they spend in the female’s body. Fully-grown adult hissing cockroaches can live for two to three years in the wild.

They’ll face dangerous predators and struggle through harsh dry seasons but these cockroaches have developed a few specific adaptations that let them survive the sometimes-severe tropical conditions.

Madagascar: The Hissing Cockroach Capital of the World

Map illustration of the Madagascar Hissing Cockroach range.

Madagascar hissing cockroaches live almost exclusively on their native island of Madagascar, off the east coast of Africa. Madagascar is the fourth-largest island in the world and is home to thousands of species of insects. While many other cockroach species have spread globally by riding on trading ships, this wild African cockroach has remained exclusive to Madagascar. Outside of the island, these insects exist only in captivity.

Hissing cockroaches commonly live on forest and jungle floors, crawling among fallen leaves, branches and decaying plant material. They’ve also been observed living in tree holes and hiding beneath the loose bark while they rest during the day. Rotting wood and fallen fruit are typical food sources for these insects, who need very little to survive.

The African hissing cockroach lives in large colonies. Within the colonies, adult males are very territorial and will aggressively defend their space from intruders. A male might claim a specific rock or a fallen log for months at a time, rarely leaving its territory. These roaches hiss loudly to enforce the hierarchy of the colony and to ward off intruders.

Madagascar hissing cockroaches don’t live in homes or buildings naturally. Since they are wingless cockroaches and aren’t attracted to light, there’s very little chance these cockroaches will enter a human dwelling.

This insect is considered a species of “least concern” by the International Union for Conservation of Nature (IUCN). This means the population of Gromphadorhina portentosa in the wild is steady and remains strong despite its limited distribution and ongoing environmental changes.

These giant cockroaches aren’t without predators, though. Madagascar is a huge island with a massive diversity of animal species and the hissing cockroach is an essential part of its food chain. Cockroaches are food for a variety of predators, such as arachnids and lizards. Some mammals, including tenrecs and birds, eat roaches, too.

Fresh Fruits and Fighting: Diet and Behavior of Hissing Cockroaches

Madagascar hissing cockroaches are nocturnal and negatively phototactic—which means they’re frightened by light. Because of this, they’re most active after sunset. Rainfall seems to make them especially active, probably due to the increased humidity. They spend the night searching in the dark for fallen fruits and plant detritus on the ground.

What do Madagascar hissing cockroaches eat?

Hissing roaches are omnivorous. They’re called detritivores, which means they feed on dead organic material, including plant parts and animal waste. Hissing cockroaches take in most of their water requirement from the fallen fruit they love to eat.

In addition to fruits, their food sources include insect carcasses, fungi and smaller insects. They also hydrate by drinking the dew from plants.

The cockroaches’ status at detritivores impacts more than their own feeding behavior—they also act as important parts of the forest ecosystem, breaking down decaying organic material and recycling those nutrients.

How do they protect themselves?

The hissing cockroach has a trick up its sleeve that it uses when threatened: it can tuck its head beneath the front of its thorax to make it appear like a larger, scarier insect. In this position, the cockroach’s horns protrude like a dangerous, armored helmet.

Madagascar hissing cockroaches have also been observed gathering tightly together to retain moisture during dry spells. These bugs dehydrate quickly and, while the tropical Madagascar climate usually provides plenty of moisture, it seems the cockroaches have developed a defense mechanism against the long dry seasons.

Fight Club: Epic Battles Between Madagascar Hissing Cockroaches

Male hissing cockroaches battle for two reasons: territorial dominance and mates. Usually, a fight starts when one male enters the territory of another.

During these clashes, male cockroaches ram into each other with their horns and their bodies, pushing and hissing loudly. Size generally determines which animal will be victorious but hissing is another key factor.

Cockroaches gauge their opponent by its hisses. Typically, the winning cockroach hisses more than the loser. These fights almost never result in physical injuries to the losing roach; they’re simply shows of dominance.

In a clash over territory, the defending cockroach will try to push the intruder out of his arena. This is a way to reinforce the hierarchy within the colony. Since several mates might be present within a male’s territory, it’s also a move to protect the cockroach’s offspring.

The cockroach who wins one of these blockbuster battles sometimes stilts, or raises its body high off of the ground. Scorpions exhibit similar behavior when they raise their tails high over their heads, lifting their bodies in the process. Along with hissing, stilting is one of the dominant cockroach’s intimidation tactics.

Cockroaches in Captivity

Madagascar hissing cockroaches are popular insects kept in captivity around the world. They’re frequently raised in laboratories and zoos for research and exhibition purposes. They’re also commonly used in classroom demonstrations, where students can learn about insect biology, the molting process, the cockroaches’ aversion to light and the importance of their place in the ecosystem.

Madagascar Hissing Cockroaches as Pets

Cockroaches have a reputation for being hardy survivors and this makes them great household pets for beginners. The Madagascar hissing cockroach is an especially fascinating pet because of its striking color, unique horns (in the males) and signature hissing sound.

You can fairly easily match their wild habitat in an enclosure (fish tanks, terrariums, etc.) with a log or piece of driftwood, some leaf litter and plenty of humidity. Wood chips and damp peat are common types of bedding that let the insects burrow to escape the light. You’ll want to purchase an enclosure with a secure lid because these cockroaches can easily climb the glass or plastic sides.

You can feed them fresh produce such as fruits and vegetables (which is part of their diet in the wild). They’ll also thrive on dry dog food or a similar pellet food that contains plenty of protein. Pet hissing cockroaches can be purchased from local pet shops or through live delivery online, and live for up to five years with proper care.

Madagascar hissing cockroaches are most vulnerable as nymphs, just after they’ve molted. During this time, their new exoskeleton is still hardening, so pet owners shouldn’t touch or handle the roaches until they’ve darkened in color.

Before purchasing Madagascar hissing cockroaches as pets, you should research your state’s requirements and find out if you need a permit to raise them. They’re considered invasive species in most places and shouldn’t be removed from their enclosure.

An Incredible Insect

The Madagascar hissing cockroach sets itself apart from other cockroaches among the jungles of its native island. With its horns, its hiss and its impressive colors, the hissing cockroach is the royalty of the cockroach world.

Through environmental changes and dry seasons, these cockroaches carry on, scavenging relentlessly for food and engaging in heated battles. Their dramas play out every day among the fallen leaves of the forest floor and, though they might be difficult to find, their hisses make them well-known to the rest of the tropical ecosystem of Madagascar.

Frequently Asked Questions

Do Madagascar hissing cockroaches bite?

Madagascar hissing cockroaches don’t bite humans or other animals. When they clash with other cockroaches, they battle by ramming each other with their horns. They defend themselves by hissing loudly. There’s no risk of being bitten by these insects.

How does the Madagascar roach reproduce?

Madagascar hissing cockroaches give birth to live young. Unlike most other cockroach species, which deposit their egg cases before the eggs hatch, the female hissing cockroach carries her egg case within her body and continues to carry the nymphs within her body after they’re born.
Baby hissing cockroaches remain in their mother’s body for one to two months before emerging as nymphs in their first instar.

What are Madagascar hissing cockroaches’ predators?

This fascinating African roach is an essential part of Madagascar’s food chain. They’re a food source for several kinds of predators, including birds, reptiles and arachnids.

Sources

  1. Clark, Debbie and Donna Shanklin. Madagascar Hissing Cockroaches. University of Kentucky College of Agriculture, Food and Environment. Retrieved from https://entomology.ca.uky.edu/ef014
  2. Madagascar hissing cockroach. Oregon Zoo. Retrieved from https://www.oregonzoo.org/discover/animals/madagascar-hissing-cockroach
  3. McLeod, Lianne (2019) Keeping Madagascar Hissing Cockroaches as Pets. The Spruce Pets. Retrieved from https://www.thesprucepets.com/madagascar-hissing-cockroach–1236891
  4. Madagascar Hissing Cockroach. South Carolina Aquarium. Retrieved from https://www.scaquarium.org/our-animals/madagascar-hissing-cockroach/
  5. Mulder, Phil and Andrine Shufran (2017) Madagascar Hissing Cockroaches: Information and Care. Oklahoma State University Extension. Retrieved from https://extension.okstate.edu/fact-sheets/madagascar-hissing-cockroaches-information-and-care.html

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