The park--one of the most varied within the park system--has 11 ecological habitats, from high rainforest to herbaceous marsh communities. Fronting the sea is the seemingly endless expanse of beach. Behind that is a narrow lagoon, connected to the sea at one end and fed by a river at the other, which parallels the beach for its full 35-km length. Back of the lagoon is a coastal rainforest threaded by an infinite maze of serpentine channels and streams fed by rivers flowing from the central mountain ranges and by the torrential rains that fall in the area. On the periphery of the forest lies a complex of swamps.

Tortuguero shelters a fabulous array of wildlife, including more than 300 bird species, among them the great green macaw; 57 species of amphibians and 111 of reptiles, including three species of marine turtles; 60 mammal species, including 13 of Costa Rica's 16 endangered species, including jaguars, tapirs, ocelots, cougars, river otters, and manatees. Commonly seen birds include toucans, aricaris, oropendolas, swallow-tailed hawks, several species of herons, kingfishers, anhingas, parrots, and jacanas. The wide-open canals make viewing easier than at many other parks--superb for spotting crocodiles, giant iguanas, and basilisk lizards basking atop the branches, swallow-tailed hawks and vultures swooping over the treetops, and caimans luxuriating on the fallen raffia palm branches at the side of the river. One of my favorite pastimes is to watch bulldog bats skimming through the mist that rises from the water and scooping up a fish right on cue. Amazing! That hair-raising roar? A male howler monkey that has misjudged a leap and hit a tree with legs spread apart (this, at any rate, was the explanation given by one irrepressible guide).

The western half of the park is under great stress from logging and hunting, which have increased in recent years as roads are cut into the core of the rainforest from the west, north, and south. The local community and hotel and tour operators are battling a proposed highway sponsored by banana and logging interests into the region between Tortuguero and Barra del Colorado. The Tortuguero Conservation Area Project, Area de Conservación y Desarrollo Sostenible de las Llanuras del Tortuguero, Apdo. 338, Guápiles, tel. 710-2929, fax 710-7673, works to protect the region and publishes literature on local ecology. Particularly threatened is the large mammal population.

About 50,000 tourists a year come here to explore the forests and swamps of Tortuguero National Park and to see any of four species of turtles that nest on the beach. The recent boom had spawned fears that the park was becoming overloaded with tourists (there were only 240 visitors in 1980). Help by carrying out anything you bring in. Rubbish disposal is a serious problem at Tortuguero: leave no trash.

Entrance is $6, payable at the Cuatro Esquinas ranger station (park headquarters), tel. 710-2929, fax 710-7673, at the southern end of Tortuguero village, or at Estación Jalova, at the park's southern end (45 minutes by boat from Tortuguero village). You can also buy a four-day pass ($10) that includes access to Barra del Colorado Wildlife Refuge. There's no fee to travel along the canals via the park en route to/from Tortuguero village.