Bug FAQMadagascar Hissing Cockroach
Gromphadorhina portentosa · Order: Blattodea · Family: Blaberidae
Also called: Madagascan hissing cockroach, giant Madagascan hissing cockroach, giant hissing cockroach, hissing cockroach
Adult Madagascar hissing cockroaches grow to about 5 to 7.5 cm (2 to 3 in) long. They are native to Madagascar and are usually found in rotting logs, preferring places they can climb. In captivity they eat fresh vegetables and high-protein pellets such as dry dog food, and females give birth to live young after carrying the ootheca inside.
Source: Wikipedia
How to recognize it
Males have thicker, hairier antennae and pronounced bumps on the pronotum, unlike females.
Source: Wikipedia
Size
They reach 5 to 7.5 cm (2 to 3 in) at maturity.
Source: Wikipedia
Where it lives
In the wild they live in rotting logs on Madagascar. They like to climb, so any enclosure should be checked for climbability.
Source: Wikipedia
What it eats
Their diet is mainly vegetable material. They also accept fresh vegetables and high-protein pellet foods like dry dog food.
Source: Wikipedia
Life cycle
Females keep the ootheca inside and release live nymphs after they hatch (ovoviviparity). In captivity they can live up to five years.
Source: Wikipedia
Lookalikes
They are one of about 20 large hissing roach species from Madagascar and are often confused with G. oblongonota and G. picea.
Source: Wikipedia
Where it is found in the US
Recorded in 4 of 51 states and DC. Most records: Michigan, Utah, Ohio, South Carolina.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Months it is reported in the US
Source: GBIF
Questions people ask
How big do Madagascar hissing cockroaches get?
Adults reach about 5 to 7.5 cm (2 to 3 in) in length.
Source: Wikipedia
Where are Madagascar hissing cockroaches from?
They are native to Madagascar and are typically found in rotting logs.
Source: Wikipedia
What do Madagascar hissing cockroaches eat?
They feed on fresh vegetables and can be given high-protein pellet foods such as dry dog food.
Source: Wikipedia
How long do Madagascar hissing cockroaches live?
In captivity they may live up to five years.
Source: Wikipedia
Same family (Blaberidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Madagascar_hissing_cockroach
Look it up elsewhere: GBIF · iNaturalist · BugGuide · Wikipedia
Text written 2026-10-23 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-23.