The wildlife that calls Caño Negro home includes a staggering variety of birds such as storks, cormorants, kingfishers and egrets. You should be able to tick off a number of the heron species that inhabit the riverbanks (including green, boat-billed and rufescent tiger herons), along with northern jacana and purple gallinule. The lagoon itself is a good place to spot the elegant, long-limbed white ibis; its shimmering dark-green cousin, the glossy ibis; and perhaps the most striking of all the reserve’s avifauna, the roseatte spoonbill, a pastel-pink bird that is usually seen filtering the water with its distinctive flattened beak. The most common species are the sinuous-necked anhingas (snakebirds), who impale their prey with the knife-point of their beaks before swallowing, though Caño Negro is also home to Costa Rica’s only colony of Nicaraguan grackle.
Reptiles are abundant, particularly the large caiman that lounge along the river and on the fringes of the lagoon, though you’ll also spot plenty of pot-bellied iguanas. Look out, too, for the strikingly green emerald basilik lizard; swimming snakes, heads held aloft like periscopes, bodies whipping out behind; and the various turtles (yellow, river and sliding) that can be seen resting on logs at the water’s edge.
Large mammals that live in Caño Negro include pumas, jaguars and tapirs, but these private creatures are rarely spotted. Howler monkeys are at least heard if not seen – it helps to have binoculars to distinguish their black hairy shapes from the surrounding leaves in the riverside trees – though it takes a good guide to pick out a sloth, camouflaged by the green algae often covering their brown hair. The rows of small grey triangles you might see on tree trunks are bats, literally hanging out during the day.
Perhaps the reserve‘s most unusual inhabitant (in the wet season, at least) is the tropical garfish, a kind of in-between creature straddling fish and reptile. This so-called living fossil is a fish with lungs, gills and a nose, and looks oddest while it sleeps, drifting along in the water.