Lençóis Maranhenses

Lençóis Maranhenses National Park
IUCN category II (national park)
Lençóis Maranhenses National Park
Location	Northeastern Maranhão, Brazil
Coordinates	Coordinates: 02°32′S 43°07′W / 2.533°S 43.117°W / -2.533; -43.117
Area	1550 km²
Designation	National park
Established	1981
Governing body	IBAMA

Lençóis Maranhenses National Park (Parque Nacional dos Lençóis Maranhenses) is a national park located in Maranhão state, in northeastern Brazil, just east of the Baía de São José, between 02º19’—02º45’ S and 42º44’—43º29’ W. It is an area of low, flat, occasionally flooded land, overlaid with large, discrete sand dunes. It encompasses roughly 1,500 km² (580 sq mi), and despite abundant rain, supports almost no vegetation. The area became a National Park on June 2, 1981.

Composed of large, white, sweeping dunes, at first glance Lençóis Maranhenses looks like an archetypal desert, but in fact it is not an actual one. Lying just outside the Amazon Basin, the region is subject to a regular rain season during the beginning of the year. The rains cause a peculiar phenomenon: fresh water collects in the valleys between sand dunes and is prevented from percolating down by a layer of impermeable rock which lies underneath the sand. The resulting blue, green and black "lagoons" are surrounded by the desert-like sand, and reach their fullest between July and September.

The lagoons have large numbers of fish that arrive when the lagoons are at their fullest after July, when they are interconnected to rivers such as the Rio Negro. One species of fish, the wolf fish or tiger fish (Hoplias malabaricus) stays dormant in the mud and moist areas after the majority of the water has evaporated, re-emerging during the next rainy season.

According to local folklore, the region was inhabited by Caeté Indians, who woke up one day to find their town covered by sand.

The national park status serves only as a means of protecting the area's ecology; consequently many people reside in the park, as is also the case with nearby Jericoacoara. The inhabitants work primarily as fishermen during the rainy season. During the dry season, many leave for neighboring regions to work small plots of land.

Located on the northeastern coast of the state of Maranhão by the banks of the Preguiças River, the park embraces the municipalities of Humberto de Campos, Primeira Cruz, Santo Amaro do Maranhão and Barreirinhas, the latest serving as the main jumping off point into the protected park.