Northern Melanesia is one of the most backward and least known regions in the world. Geographically it embraces the northern and western islands of the great archipelagoes that rim the Pacific Ocean basin to the north and northeast of Australia, just south of the equator. Ethnically the term refers to the sausage-shaped, insular realm of Melanesia, where melanin, or dark skin pigment, is a prevailing and conspicuous racial characteristic of some two million Pacific Islanders. Most of the culturally retarded peoples of Melanesia are of Papuan or Melanesian racial stocks, or blends of the two. At the western extremities of Melanesia, however, infusions of Malay stock are revealed in the generally lighter skin color of the people, especially along the coasts of western New Guinea and the islands adjacent. In the eastern islands ( eastern Fiji) Polynesian infusions of blood account for the lighter color of some groups. In the interior of Dutch New Guinea, moreover, there are a number of valleys inhabited by relict Negrito or "little Negro" tribes; in the more important coastal towns, on neighboring plantations, and in the mining districts live small numbers of Whites, and on some of the islands Indians, Chinese, Javanese, and others.
The islands that comprise northern Melanesia extend from the immediate vicinity of the equator to 12° south latitude, and from 130° to nearly 155° east longitude. The more important of these are New Guinea, together with its western outliers such as Waigeo, Japen, and the Schouten group, and its eastern outliers, which include the Louisiade Archipelago, the D'Entrecasteaux group, and lesser near-by islands; the Bismarck Archipelago, dominated by New Britain and New Ireland; and the Admiralties, of which Manus is the largest and most important island. The larger islands are mostly quite rugged, with elevations up to 9000 feet on New Britain and over 16,000 feet in western New Guinea. Some of the smaller islands--primarily those of volcanic origin--are hilly to mountainous, but many of the others are low, flat, and swampy, or else low, relatively flat, and sandy or rocky. The climate of the lower elevations (below about 3000 feet) is mostly warm to hot and humid to wet. In places and at times, however, the equatorial heat is tempered by monsoon winds and landand-sea breezes. Southern New Guinea in the vicinity of Port Moresby has a subhumid climate resulting, apparently, from rainshadow effects and the direction of the monsoonal air flow that parallels the coast much of the time. Intermediate elevations (3000 to 7000 feet) range from warm to cool and from humid to wet, depending chiefly on their degree of exposure to wind and sun. Higher elevations (above 7000 feet) are likely to be rather wet, cloudy, and cold.
The vegetation pattern of northern Melanesia reflects the diversity of its surface configuration, climates, soils, and cultural or human activities. Rainforest and swampforest prevail in the lowlands and on the mountain slopes up to 5000 feet or more, except where native clearing and cultivation or commercial plantation enterprises have modified the indigenous plant associations. Relatively pure stands of pine and other softwoods are found in places on the mountain slopes above 5000 feet, whereas mossy forest dominates most of the higher, wetter elevations. Above 15,000 feet in western New Guinea, perpetual snow and ice prevent the development of any type of flora; elsewhere, rock outcrops, recent volcanic activity, sour soils, coastal sands, and poor drainage modify the pattern locally. Wherever cultivation has taken place, significant changes have been wrought in the vegetation landscape. Thus instead of rainforest on some of the humid coastal lowlands, we now find coconut and other plantations (including cacao and citrus), or grasslands composed of coarse, tall, tropical grasses induced by the shifting cultivation practices of the natives. Such grasslands also extend into many of the remote interior valleys of highland New Guinea. Finally there are a number of specialized plant associations in addition to the above, such as halophytic beach plants in the immediate vicinity of the coasts where salt spray restricts rainforest development; sago palm forests spottily distributed through the lower, wetter rainforest; mangrove swamps in the vicinity of the larger river mouths; and bamboo and pandanus thickets in the intermediate mountain zone.
The native fauna of northern Melanesia, like the flora, is essentially a composite of Asian, Australian, and indigenous elements. In the fauna, as in the flora, profound local changes have resulted from human occupation, both native and European. Among the more curious or more widely publicized forms of animal life that preceded man into this Melanesian environment are: cassowaries, or large, ostrichlike birds; snakes, including the giant pythons that are capable of swallowing a live pig or a man; lizards, the most impressive of which is the iguana, which may attain a length of 3 or 4 feet; the gorgeously plumed but raucous-voiced birds of paradise, of which the rust-red and the white species are the most numerous and the azure blue perhaps the rarest and most-sought-after for its feathers; the wallaby, or small kangaroo; the kangaroo rat; the cuscus, a unique marsupial; the snow-white cockatoo; the crocodile that infests the larger rivers; giant, night-flying moths; the "flying-fox," a kind of bat; and a myriad of lesser animal forms. In terms of nuisance value, there can be little doubt that honors go to certain insects, such as the malaria mosquito (Anopheles punctatum), the mite that spreads the deadly scrub typhus, leeches, fleas, lice, and the common housefly, although the natives on the whole have more fear of crocodiles and pythons, and a variety of snails, leaf-chewing and juice-sucking insects cause more damage to crops. Wallabies are an important source of native food, as are also other marsupials, birds, snakes, lizards, and various rodents. Fish, shellfish, turtles, and other forms of sea life such as sea-slugs, the sea-cow, (dugong or manatee), sea-worms, and the like are also used for food by natives living along the coasts, and trepang, pearls, pearl shell, and tortoise shell are commercial exports from the region. Natives are said to have taken fish larger than a man from the Membaramo River in western New Guinea.