Local family fishing with a gill net as the tide comes in during the afternoon near the west end of Lençois Maranhenses. They were catching small fish 8 inches long called "Saúna". They had a temporary shelter for shade while waiting for the tide.
Lençois Maranhenses National Park is a coastal dune field (measuring some 155,000 hectares) that is flooded with freshwater lakes during the January to May rainy season. Strong prevailing winds from the East mobilize the barchan dunes during the dry season and, combined with the equatorial sun, evaporate the lakes and prevent permanent vegetation from taking root. The dunes are composed of quartz grains that are eroded from the granite and washed down from the Parnaiba River and then carried north by ocean currents before being deposited on the coast of Lençois Maranhenses. The name means "bed sheets of Maranhão Province", as from above they resemble undulating sheets of pure white.