Madagascar Hissing Cockroach (Gromphadorhina sp)

Madagascar Hissing Cockroaches are one of the world's largest cockroach species and among the most recognisable invertebrates kept as pets. They're famous for one thing: the loud hissing sound they produce by forcing air through specialised breathing holes. Unlike most insects that make noise by rubbing body parts together, hissers use a respiratory mechanism more similar to how vertebrates vocalise. They're docile, wingless, easy to care for, and surprisingly personable—making them a classic choice for anyone interested in keeping invertebrates.

Species Information

• Scientific name: Gromphadorhina sp. (most commonly G. portentosa, though several similar species are often sold interchangeably)
• Common names: Madagascar Hissing Cockroach, Hisser, MHC, Malagasy Hissing Cockroach
• Origin: Madagascar
• Adult size: 5–7.5cm (2–3 inches), occasionally up to 10cm
• Lifespan: 2–5 years
• Difficulty: Easy

Taxonomy Note

There are around 20 species of large hissing cockroaches from Madagascar, and pet dealers frequently confuse them with one another. Gromphadorhina portentosa is the most commonly kept species, but G. oblongonota and G. picea are also regularly sold—often under the same name. Care requirements are essentially identical across species, so this rarely matters for keepers.

Appearance

Hissing cockroaches have a distinctive look:

• Body: Oval-shaped, shiny brown to dark mahogany, almost black in some individuals
• Exoskeleton: Thick, hard, and waxy
• Wings: Completely wingless (unlike most cockroaches)
• Legs: Equipped with pads and hooks that allow them to climb virtually any surface, including smooth glass
• Size: Among the largest cockroaches in the world—adults are substantial, impressive insects

Sexual Dimorphism

Males and females are easy to tell apart once mature:

• Males: Have prominent "horns" (raised bumps) on the pronotum behind the head. Antennae are hairier. Generally more aggressive (toward other males, not handlers). Slightly smaller than females.
• Females: Lack horns or have only very small bumps. Antennae are smoother. Tend to be larger and wider than males.
• Underside: Males have three smaller segments at the rear of the abdomen; females have one larger segment.

The Hissing

The defining feature of these cockroaches is their ability to hiss. They produce sound by forcing air through modified breathing pores (spiracles) on their abdomen. This is unusual—most insects make noise through stridulation (rubbing body parts together) or vibrating membranes.

Types of hiss:

• Disturbance hiss: A loud, snake-like sound used when startled or threatened. All cockroaches from the fourth moult onward can produce this.
• Courtship hiss: Males use this to attract females.
• Fighting hiss: Males hiss during territorial disputes. Winners hiss more than losers—hissing helps establish hierarchy.

The hiss is genuinely loud and can startle people who aren't expecting it. It's part of what makes these cockroaches interesting to keep.

Behaviour

• Nocturnal: Most active at night, spending daytime hours hiding
• Docile: Generally calm and tolerant of handling—one of the more "handleable" invertebrates
• Non-aggressive: Cannot bite humans (mouthparts aren't strong enough) and pose no threat
• Climbing: Excellent climbers capable of scaling smooth glass—secure enclosures essential
• Social: Live communally in the wild and do well in groups in captivity
• Male aggression: Males will fight other males for territory and females, ramming each other with their horns and pushing with their abdomens. This looks dramatic but doesn't cause injury.
• Territorial: Males may claim and defend small territories (a rock, a piece of bark) for extended periods

Despite being cockroaches, hissers are clean animals that groom themselves frequently. They don't have the pest associations of household cockroach species.

Enclosure Setup

Container

• Glass or plastic aquarium, plastic storage container, or purpose-built terrarium
• Size depends on colony size—a 5–10 gallon tank suits a small group; larger colonies need proportionally more space
• Secure, well-ventilated lid is essential
• Escape prevention: They can climb smooth surfaces. Apply a 5cm band of petroleum jelly around the top inside edge of the enclosure to prevent escapes. This is important.

Substrate

Several options work:

• Coconut fibre (coco coir)
• Peat moss
• Sphagnum moss
• Wood chips (not cedar or pine)
• Some keepers use no substrate at all for easier cleaning

If using substrate, keep it slightly moist but not wet.

Hides and Climbing

• Egg cartons: The classic choice—cheap, provides lots of surface area and hiding spots, easy to replace
• Cork bark
• Cardboard tubes
• Vertically placed bark or branches for climbing

Hissers like dark hiding places and will spend most of the day tucked away. Providing adequate hides keeps them comfortable and reduces stress.

Temperature

• Survival range: Mid-teens°C (60s°F) to around 35°C (95°F)
• Optimal range: 24–29°C (75–85°F)
• Breeding: Warmer temperatures (27–32°C / 80–90°F) encourage faster breeding
• Room temperature: They'll survive at typical UK room temperatures but will be less active and breed slowly

If supplemental heating is needed, heat mats on the side of the enclosure or ceramic heat emitters work well. Provide a temperature gradient so roaches can move to their preferred temperature zone.

Humidity

• Range: 50–70%
• Maintenance: Occasional misting, keeping substrate slightly damp, or providing a water source
• Moulting: Adequate humidity helps ensure successful moults

They're reasonably tolerant of humidity variation and don't require precise conditions.

Water

Provide water via:

• Water crystals/gel (safest option—prevents drowning)
• Cotton wool or sponge soaked in water
• Shallow dish with pebbles (to prevent drowning)
• Misting (they'll drink droplets)

Fresh vegetables and fruit also provide moisture.

Diet

Hissing cockroaches are detritivores and omnivores—they're not fussy eaters:

Staples:

• Dry dog or cat food (high protein)
• Fish flakes
• Chicken laying mash
• Commercial roach chow

Fresh foods:

• Vegetables: carrots, courgette, sweet potato, leafy greens, Chinese cabbage
• Fruit: banana, apple, orange, melon (they love overripe fruit)

Notes:

• They're not enthusiastic about lettuce or spinach
• Remove uneaten fresh food before it moulds (within a few hours for fruit)
• Dry food can be left available constantly
• Feeding carrots and other carotenoid-rich foods can enhance their colour

Breeding

Hissing cockroaches breed readily in captivity:

• Reproduction: Ovoviviparous—females carry eggs internally and give birth to live nymphs
• Gestation: Approximately 60 days
• Litter size: 15–60 nymphs per brood (typically 30–40)
• Broods per year: 2–3 under good conditions
• Sexual maturity: 3–6 months depending on temperature
• Development: Nymphs undergo 6 moults over approximately 7 months to reach adulthood

Breeding behaviour:

• Males court females with hissing and antennal contact
• Mating occurs end-to-end and lasts around 30 minutes
• Females are not receptive immediately after moulting—receptivity begins about 20 days later once their exoskeleton hardens

Breeding rate is moderate compared to some feeder species—don't expect explosive population growth. Warmer temperatures (27–32°C) speed things up considerably.

Handling

Hissing cockroaches are one of the better invertebrates for handling:

• Generally calm and slow-moving
• Tolerate regular handling well and can become quite "tame"
• Cannot bite—mouthparts aren't capable of harming humans
• May hiss when first picked up (this is normal and harmless)
• Legs are spiny and can feel prickly but aren't harmful

Note: Some people develop allergies to hissing cockroaches with prolonged exposure and frequent handling. If you notice skin irritation or respiratory symptoms, reduce contact.

Feeder Use

Hissers can be used as feeder insects for larger reptiles, amphibians, and invertebrates, though they have limitations:

• Pros: Good size for large animals, easy to gutload, relatively soft-bodied for their size
• Cons: Breed more slowly than dedicated feeder species like dubia. Adult males have horns and spiny legs that can make them uncomfortable or potentially harmful for some predators to eat. Hard adult exoskeletons can be difficult for some animals.
• Best practice: Use nymphs or adult females as feeders. Consider offering freshly killed adults to prevent struggling and potential injury from legs.

For serious feeder production, faster-breeding species like dubia or orange-head roaches are more practical. Hissers work better as pets or as occasional feeders for larger animals.

Mites

Hissing cockroaches commonly host a species of mite (Androlaelaps schaeferi) that lives on their bodies, particularly at the base of the legs. These mites have a commensal relationship—they eat debris and help keep the cockroach clean. They're not harmful to the roaches and don't affect humans. If you see small mites on your hissers, this is normal and not a cause for concern.

Care Summary

• Temperature: 24–29°C optimal (room temperature acceptable, warmer for breeding)
• Humidity: 50–70%
• Substrate: Coco coir, peat moss, or bare floor
• Hides: Egg cartons, cork bark, cardboard tubes
• Diet: Dry dog food, fish flakes, vegetables, fruit
• Water: Gel crystals, soaked sponge, or shallow dish with pebbles
• Escape prevention: Petroleum jelly barrier around top of enclosure
• Lifespan: 2–5 years
• Breeding: Live-bearing, 30–60 nymphs per brood, moderate reproduction rate

Who Are They For?

Madagascar Hissing Cockroaches suit:

• Beginners: Hardy, forgiving, and easy to care for
• Educational settings: Popular in classrooms and zoos for teaching about insects
• Handlers: One of the most handleable invertebrate species
• Anyone wanting an unusual pet: They're genuinely interesting animals with observable behaviours
• Keepers who want audible insects: The hissing is unique and entertaining

They're not ideal for:

• High-volume feeder production (too slow-breeding)
• Anyone who can't secure enclosures properly (they will escape if given the opportunity)

Madagascar Hissing Cockroaches have been popular pets for decades for good reason. They're large, impressive, surprisingly docile, and genuinely interesting to observe. The hissing alone makes them memorable—it's loud, distinctive, and never fails to get a reaction. If you're looking for an easy, low-maintenance invertebrate with genuine character, hissers are hard to beat.