International audience ; The present essay is based on a non-exhaustive search through a corpus of literature on early expeditions across New Guinea. It first focuses on the images and descriptions of certain Dayak tribes from Dutch Borneo that were conveyed and circulated to the Dutch East Indies and, later, the wider Western world through books, articles, and scientific lectures that stressed the key role these tribes played in the success of the important expeditions of the turn of the twentieth century across Borneo; in a second part, on the role that teams from these same and/or related Dayak tribes, recruited steadily and en nombre as “jungle and river experts”, played in ensuring the success of major exploration expeditions across Dutch (western) New Guinea in the first four decades of the twentieth century; in a third part, on the “who, whence, why, etc.” of those Dayak crews, and on the rationale behind their continued appearance in New Guinea expeditions; and in a final part, on the perceptions and relations that developed amongst these expeditions’ various categories of field personnel, particularly the unanticipated affinity and alignment between the Dayak support crews and the Western senior staff.