 Mounting is an awkward process and the male must stretch and tense to maintain equilibrium in a slanting position.The concave underside of the male's shell helps him to balance when straddled over the female's shell, and brings his cloacal vent (which houses the penis) closer to the female's dilated cloaca.During mating, the male vocalises with hoarse bellows and grunts, described as "rhythmic groans".