From approximately 400 BC to 1600 AD, Marajó was the site of an advancedPre-Columbian society called theMarajoara culture, which may have numbered more than 100,000 people at its peak. Today, the island is known for its largewater buffalo population, as well as thepororocatidal bore periodically exhibited by high tides overcoming the usual complex hydrodynamic interactions in the surrounding rivers. It is the second-largest island inSouth America, and the35th largest island in the world.
With a land area of 40,100 square kilometres (15,500 sq mi) Marajó is comparable in size toSwitzerland. Its maximum span is 295 kilometres (183 mi) long and 200 kilometres (120 mi) in perpendicular width.[1]
The island is situated just south of theEquator. Its Northern cost, which runs almost parallel to it, is calledContracosta.[2] Due to its location at the mouth of theAmazon River, archeologistHelen Palmatary compared the island to "an egg in the mouth of a snake".[3]
Together with smaller neighboring islands that are separated from Marajó by rivers, they form the Marajó Archipelago, with an aggregate area of 49,602 square kilometres (19,151 sq mi).[4]The archipelago is contained in the 59,985 square kilometres (23,160 sq mi)Marajó Archipelago Environmental Protection Area, a sustainable-use conservation unit established in 1989 to protect the environment of the region.[5]
Marajó is almost entirely flat. The island can be divided into the Western side with plains at a slightly higher elevation of around 6 metres (20 ft), and the Eastern side with swampyrainforest situated around sea level. This division can easily seen on satellite images.[2] Marajó is largely flooded during therainy season because of higher water levels of the rivers along its coast and heavy rainfall in its interior. During this season, much of the island presents itself as a large lake.[6]
There are 20 large rivers on the island. Because of the changing water levels and regular seasonal flooding, many settlements are built on stilts (Palafitas).
The island is known for thepororoca, atidal bore phenomenon in the river that creates large waves reaching 4 m (13 ft) in height. It is atourist destination, especially forsurfing of the bore.
The eastern side of the island is dominated bysavanna vegetation. There are largefazendas with animal husbandry.[6] This is also the location of Lake Arari, which has an area of 400 square kilometres (150 sq mi), but shrinks by 80% during the dry season.[7] There are large herds of domesticatedwater buffalo, which are technicallyinvasive to the island; they now number about 450,000, higher than the island's human population.[6][8] The western side of the island is characterized byvárzea forests and small farms. Lumber andaçaí palm are produced there.
To the north of the large savanna area arepalmswamps, mainly with Buriti Palm (Mauritia flexuosa) andEuterpe oleracea. During the rainy season, the swamps are flooded one meter high. Little is known about the ecology of these swamps.
The most important towns are in the southeastern portion of the island:Soure,Salvaterra, and the largest city,Breves. They feature a basic touristic infrastructure and are popular because of the generous, lightly populated beaches. The city of Soure, on the island's Atlantic coast, serves as an entry point to the island via its ferry link toBelém.
The island is shared by 16 municipalities of three microregions:
The island was the site of an advancedpre-Columbian society, theMarajoara culture, which existed from approximately 400 BC to 1600 AD. The island has been a center of archaeological exploration and scholarship since the nineteenth century.[6] Scholars from the 1980s forward have divided the pre-Columbian period into the Ananatuba phase (c. 1100 – c. 200 BC), the Mangueiras phase (c. 1000 BC – c. 100 AD), the Formiga phase (c. 100-400 AD), the Marajoará phase (c. 400-1200 AD), and the Aruã phase (1200-1500 AD).[6]
Since the 1990s, there has been debate over the origins and sophistication of Marajó's pre-Columbian society. Based on fieldwork in the 1940s and 1950s, the archaeologistBetty Meggers initially argued that the Marajoara culture had been founded by emigrants from theAndes and that the society steadily declined until its final collapse at approximately 1400 AD, due to the Marajó's poor soil fertility and other environmental factors. Megger's hypotheses subsequently became associated withenvironmental determinism. Her theory has since been rejected, however, by the archaeologistAnna Curtenius Roosevelt, who re-excavated Marajó in the 1980s. According to Roosevelt, the Marajoara culture developed independently within the Amazon and featured both intensive subsistence agriculture and major public works.[9]
Roosevelt estimated that Marajó may have had a population of more than 100,000 people at its peak.[10] The population lived in homes with tamped earth floors, organized themselves intomatrilinealclans, and divided tasks by sex, age, and skill level.
The arrival of Europeans in the sixteenth century was catastrophic to the indigenous population of the island; 90% died due to high mortality from Eurasianinfectious diseases; they lackedimmunity against these diseases that had becomeendemic in Eurasian cities.[11]
In contrast, however, during the 1918–1919 pandemic worldwide ofSpanish influenza, Marajó was the only major populated area not to have any documented cases of the illness.[12]
