 Sydney brown trapdoors are medium-to-large in size; the female is around 35 mm in length, while the male is usually around 20 mm and of a slimmer build.They are chocolate brown coloured and the males have distinct boxing glove-shaped palps, which are the appendages at the front of the head between the first pair of legs.Sydney brown trapdoors are usually shy and retiring, although the occasional individual will stand up and show its fangs if harassed inside its burrow.