Giant Hissing Cockroach Gromphadorhina oblongonota

There are some 20 species of super-sized, non-flying cockroaches endemic to Madagascar and sharing the name Madagascan Hissing Cockroach, particularly the four in this genus. This is one of the world's largest and can grow to 10cm but usually will reach only 8cm long (just over 3 inches). It is also called the Wide-horned Hissing Cockroach. It has bigger "horns" and a louder hiss than its relative G. portentosa, for which it is often mistaken.

Cockroaches are nature's recyclers and this one lives in rotting logs and leaf litter recycling wood, leaves and fruit. Like other cockroaches, adult males and females look similar and live together in large colonies including numerous subadults and nymphs at all stages of development. Males have thicker, hairier antennae than females and larger "horns"; the latter are used to fight other males (to damage their antennae). G. oblongonota generally has a more burgundy colour and older nymphs have white marks on the sides of their front half.

Unusually for cockroaches, these giants don't have wings and can't fly; however they climb well. They hiss to show displeasure or aggression by pushing air out of the tiny holes along their flanks, which can startle potential predators. They live for some 2-3 years.

G. portentosa of northern Madagascar is commonly confused with G. oblongonota of southern Madagascar, G. picea of the southwest and G. grandidieri of spiny forest in the southwest.