Caño Negro is a wonderful location to observe mammals, reptiles, and hundreds of bird species, including migratory birds at different times of the year. The refuge is located about and hour and a half from La Fortuna, and it can only be explored by boat. There are several tour providers that offer boat tours, or you can rent a kayak and explore the river on your own. Either way, this makes for a great day trip, relaxing and observing abundant wildlife along the river.
Caño Negro Wildlife Refuge is located in the northern part of Costa Rica, very near the border with Nicaragua, and covers about 10,000 hectares (almost 40 square miles). It is part of the Arenal Huetar Norte Conservation Area, and it is characterized by and band of forest along the Rio Frio river, wetlands, mostly sorrownded by ranches. In fact, conservation in the area is a result of the partnership between authorities and ranchers.
While many tours operate out of Los Chiles, only a couple of miles from the Nicaraguan border, there are several spots southwest from there where the river is accessible. Visiting the areas off the beaten path will probably make for a more relaxing experience, but there is wildlife in most areas along the river. The river is many miles long, but operators will usually navigate a few miles and then come back to the starting point. If you rent a kayak, it is recommended to paddle upstream first; even though the current is not strong, it still makes a difference when paddling for several miles. If you plan to cross the border, make sure to bring passports.
Whether on a commercial boat on paddling on a kayak, watch for alligators, iguanas and lizards -some of which run on the surface of the water. Mammals that can be spotted include monkeys -capuchino, spider and black howler- as well as sloths; larger animals such as jaguars and tapirs also inhabit the area, but are very difficult to see. There are many species of birds that can be observed. Many species winter in the area, when the water is low. During the rainy season, from May to October, there is more water on the river, being fed from the mountains and forests to the south. While many of the migrating birds will be up north for the summer, there are still many resident species that are visible, including anhingas and cormorants, egrets, storks, parrots and many others.
As in other adventures in Costa Rica, a guide is not mandatory, but it can help gain deeper knowledge of local wildlife and culture.