Kagu name "Rhynochetos", and the clade name Rhynochetidae, are derived from the Greek "rhis" meaning nose and "chetos" meaning corn, referring to the corn-shaped flaps over the nostrils. The specific name "jubatus" is derived from the Latin "iabatus" meaning crested. The name kagu is derived from the Melanesian names for the species. The species is variously known as the "kavu" or "kagou" in the Kanak languages, and as the "cagou" in French (also used as an alternative spelling in English). The kagu is a ground-living bird, in length. The weight can vary considerably by individual and by season, ranging from .
Kagu some range contraction due to hunting and predation by introduced species. Its original, pre-human distribution, and the extent to which it and its sister species "R. orarius" coexisted in lowland areas of New Caledonia, is still not fully understood and awaits further research into the subfossil record. Kagu are territorial, maintaining year-round territories of around 10–28 hectares (22–62 acres). Within the territory the pairs are solitary during the non-breeding season, and may have separate but overlapping foraging areas. Kagus make a range of different sounds, most commonly while duetting in the morning, each duet lasting about 15 minutes. The kagu's