Presently, most authorities consider the southern cassowary monotypic, but several subspecies have been described. It has proven very difficult to confirm the validity of these due to individual variations, age-related variations, the relatively few available specimens (and the bright skin of the head and neck – the basis upon which several subspecies have been described – fades in specimens), and that locals are known to have traded live cassowaries for hundreds, if not thousands of years, some of which are likely to have escaped/been deliberately introduced to regions away from their origin.