Although fauna may be very abundant in the neo tropical rain forest, the density of the vegetation can make it very difficult to spot birds and mammals. The best way to spot things is of course using binoculars, but not while searching between trees, the best is to search for abnormal movement among branches and leaves, some sort of shaking movement quite different from the typical movement produce by wind or breeze. Once you have spotted this, keep your eyes in spot and put on your binoculars, then you will clearly see your specie...
Even though Costa Rica's list of mammals is a bit over 200 hundred species, nearly half of them are bats. These are very important pollinators and dispersers of seeds in the rain forest, because different from northern bats, here very few of them eat insects, but are fruit and pollen eaters, and one is actually a fisher bat (which lives here at Tortuguero Canal).
That leaves us with about 100 species of mammals, then many are rain forest rats, about 9 are opossums, about 3 are squirrels, then we have 4 species of monkeys (3 that can be seen in Tortuguero Canal) 5 species of wild cats, some weasels (one is so big it's similar to wild cat) 2 species of peccaries, 2 or 3 species of ant eaters, 3 species of sloths, 2 species of deer, 1 porcupine (rodent), 2 species of rodents, one is as big as a medium-sized dog (the other looks like a small-size dog), 2 species of river otters, 1 tapir and some more species...
Among birds, we find more than 875 species in the country, and insects, we may find between 350 to 500 thousand depending on the opinion of different entomologists.
In our tour "Ecological Experience" is where we can observe more fauna, plus, the tour includes a short nice ride in an aerial tram