The Moloch gibbon (Hylobates moloch) has long fluffy silver-grey fur, with darker markings on the chest and cap. It has long arms and legs, long fingers and reduced thumbs, all of which are adaptations for brachiation (swinging through the trees from arm to arm). Males produce simple ‘hoot’ calls, whilst the calls of females are more variable, ending in a ‘bubble’. Both sexes also give a ‘scream’ alarm call.