Red mangrove does not avoid salt; it manages it. Its arching prop roots exclude most seawater at the point of entry, and the leaves push the remainder out as crystals visible on the upper surface. That single adaptation built the tidal forest at the mouth of the Río Damas, north-west of Quepos, where a Damas Island Mangrove Boat Tour follows channels that exist only twice a day. At low water they are mud. At high water they are navigable corridors, sometimes barely four metres wide. The estuary holds four of Costa Rica's mangrove species within a short run of water. Rhizophora mangle claims the outer edge, its stilt roots colonising open silt. Avicennia germinans stands behind it, breathing through pencil-thin pneumatophores that push up through anaerobic mud. Laguncularia racemosa and Conocarpus erectus occupy the drier margin, where the forest gives way to pasture and oil palm. Each band traps sediment. Together they hold the coastline in place, absorb storm surge, and shelter the juvenile snapper and snook that later stock the open Pacific. The system matters now for reasons that have little to do with scenery. Costa Rica protects its mangroves as national wetland patrimony, and the Damas channels sit inside that framework, close enough to Manuel Antonio that day traffic could easily have overwhelmed them. Instead, boat numbers stay small and engines stay slow. Damas Island Mangrove Boat Tour tours run on flat-bottomed craft drawing only a few inches, operated by crews who read the tide table before the calendar. Locally the outing is still called a tour de manglares. Naturalists working the same bends year after year log their sightings — silky anteater, boat-billed heron, mangrove tree crab — as a rough running census. Wildlife here is layered rather than displayed. White-faced capuchins work the canopy through the middle of the day. Proboscis bats line the underside of fallen trunks in rows of six or eight, aligned nose-down against the bark. American crocodiles hold the deeper bends where the current slows. A Quepos mangrove wildlife cruise reveals these in sequence rather than all at once, and the Damas Island Mangrove Boat Tour tour that finds every one of them is a matter of tide, light and patience. The estuary redraws itself every six hours. Nothing about it is fixed, and the forest that looks impassable at dawn is a road by mid-morning.