The workers of this species are an attractive reddish color and about 10 mm in size. The queens are easily distinguished from the workers being larger at about 12 mm and having an enlarged thorax and slightly larger abdomen. Although young colonies will only have a single queen, in time most colonies will accept additional new queens and larger multi queen colonies will form.
Colonies often form several sub nests nearby which are all linked. In these larger multi queen colonies there can be around 500-800 individuals. They will excavate and crate nests in ready-made cavities, in pieces of old wood or dead bamboo stems. They also nest in the ground frequently masking use of the small burrows of other animals, and in the rainy season when humidity is high, they will create simple nest amongst the leaf litter.
In their natural habitat they mostly forage at night but can also be seen outside on dull overcast days or in areas that are heavily shaded. They do not climb but forage at ground level, although they will explore along fallen branches.
When undisturbed their movements are calm and deliberate and they slowly walk around with their mandibles set in 'trap position' probing with their long antennae. However, when their nest is disturbed, they can move quickly and will defend it by latching onto the intruder and delivering a very painful sting.
In their natural habitat during the winter and hot season when food is scarce, they only raise a small amount of brood. However, once the rainy season starts and food becomes more freely available the queens quickly start to lay more eggs and they will raise much larger broods.
The name ‘trap-jaw’ comes from their specially evolved hunting technique. They have a long pair of hooked mandibles and the workers forage with their mandibles held open at 180 degrees. The mandibles have sensory hairs on the inside and when these are touched, they automatically snap shut. The force of the mandibles closing on the pray either kills it or stuns it, and this followed with a potent sting which further paralyses the prey, enables them to catch prey which would normally quickly escape other ant species.
Ants of this genus are recorded as having the fastest self-powered predatory strike in the animal kingdom. One study on O. bauri recorded peak speeds of between 126 – 230 km hr, (78 to 143 mph) with the jaws closing in just 130 microseconds.
These ants are also capable of launching themselves into the air by snapping their jaws shut against the ground or other hard object. These strikes serve two main purposes - attack and escape. When they are attacking an intruder and are intentionally defending their nest the action flings them into the air, landing hopefully near or actually on the intruder so they can deliver a sting. This action also serves to catapult the ant away from an intruder, protecting the ant from a retaliatory strike. The distance jumped depends on the species but heights of 8 cm and a horizontal distance of 30-38 cm have been recorded.
They can be kept in captivity relatively easily and take to most types of artificial nests. They readily take both dead and live insects and sugared water. A favorite food is small newly hatched crickets which are simply put into their enclosure alive - and will be found in the ant’s brood chamber the next morning.
Summary: Because of their unusual hunting method this is a fascinating species to keep and responds well to captivity, but you should avoid handling the ants as they have a painful sting.