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Madagascar Hissing Cockroach
Gromphadorhina portentosa
One of the largest and most famous cockroaches in the world, iconic for the incredible hiss it emits when disturbed. Totally wingless, incapable of infesting homes, and surprisingly docile, it has become a highly popular pet and an exceptional detritivore for disposing of organic scraps.
- Family
- Blaberidae
- Origin
- Madagascar
- Origin
- Extra-Amazon South AmericaAfrica and Madagascar
- Tank use
- Used in 0 tanks
Share
22 °C - 30 °C
n/a
Terrestrial
50 % - 70 %
5 cm
Description
Geographical Origin and Habitat: Endemic species of the lush and ancient forests of Madagascar. They live exclusively on the ground, buried beneath giant piles of decomposing leaf litter and fallen logs, carefully avoiding direct sunlight.
Taxonomy and Genetics: Blaberidae family. Unlike domestic pest roaches (Periplaneta or Blattella), G. portentosa is a specialized forest creature, extremely slow to reproduce, unable to survive in sterile domestic environments, and incapable of flying or jumping. In captivity, they present no relevant chromatographic morphs, keeping their austere mahogany black or shiny caramel brown color.
Behavior and Habits: Very slow and peaceful crepuscular animals. Their worldwide fame derives from the incredible hiss they produce: unlike all other insects that rub body parts together, these roaches forcefully expel air through respiratory spiracles on their abdomen (exactly like the vocal breathing of vertebrates). They use the hiss in 3 ways: alarm hiss (very loud, to scare predators), fighting hiss (between rival males), and mating hiss.
Morphology and Sexual Dimorphism: Titanic, heavy insects, easily reaching 3-4 inches (8-10 cm) in length. The body is oval, heavily armored, and completely wingless in both sexes, an unusual trait among large roaches. Their feet are equipped with incredibly powerful micro-suction cups capable of scaling smooth glass and plastic. Sexual dimorphism is obvious: males possess a large pronotum (the shield over the head) adorned with two huge horn-like protuberances, which they use to ram each other during territorial fights. Females are smooth and flat.
Care and observations
Terrarium Setup: They require plastic faunaboxes or glass terrariums. Since they are formidable climbers of smooth surfaces, escape is certain unless a strip of petroleum jelly (Vaseline) or fluon is smeared along the top 2 inches of the inner walls. The setup requires only dry coco peat and an industrial amount of stacked hides: stacked egg cartons, large cork bark pieces, and rotten wood under which they will colonize.
Lighting and Heating: They shine in their tolerance, living from 72°F to 86°F (22-30°C). They are photophobic: avoid internal lamps or bright heat sources. To make them breed abundantly, a heating mat placed on the side of the faunabox to create an 82°F (28°C) hot zone is ideal, but they also thrive at household room temperature, albeit growing much slower.
Humidity and Hydration: Require medium humidity (50-70%). Pregnant females have a special need for humidity to avoid aborting their egg cases (ootheca). A tank that is too soaking wet, however, will exterminate them with mites and fungi. Perfect hydration is provided NOT with water bowls (where nymphs would drown and soil would rot), but by using water-crystals (insect water gel) or feeding abundant fresh, water-rich vegetables and fruits.
Feeding and Supplementation: They are formidable organic composting machines. Their dietary needs range from dry dog/cat kibble or fish flakes (for the proteins and vitamins necessary for molting) to scraps of carrots, apples, lettuce, and citrus. A colony will dispose of large quantities of healthy, clean food scraps, producing dry, odorless droppings (frass) that are a formidable fertilizer for house plants.
Compatibility and Cohabitation: Very sociable and peaceful with each other. Males engage in spectacular jousting matches where they headbutt with their horns for dominance, but they do not mutilate each other (ritualized combat). Mothers are known to tend to their brood for months and protect the nymphs, a very rare behavior in insects. Often kept in bioactive setups alongside giant isopods.
Health and Common Diseases: They are unstoppable tanks devoid of known diseases in captivity if kept clean. The only huge risk is caused by the keeper failing to remove fresh food before it molds: toxic green and gray fruit molds will exterminate the roach's respiratory colony in a very few days. Furthermore, in old age, they may lose their feet, reducing mobility before natural death.
Terrestrial invertebrate profile
- Diet
- Detritivoro
- Humidity
- 50 % - 70 %
- Temperature
- 26 °C
- Sociality
- Gregarious
- Venom level
- None
- Substrate depth
- 5 cm
Image gallery
Licensed images linked to the species or, when marked, to the closest representative taxon.

