Yasuni is a biodiversity sanctuary. Research conducted in the last decade reflect figures never before registered in any other area of the tropical rainforest, and even though the data might change over time, it gives us an idea of what this national park shelters: more than 2,000 species of trees and shrubbery, 204 mammal species, 610 species of birds, 121 reptile species, 150 amphibian species and more than 250 fish species. 
In one hectare of Yasuni, for example, there have been 650 tree species recorded, which represents more than those found in the whole continent of North America.The land forest makes up the main ecosystem of the park. In Yasuni there are trees that can reach the height of 50 meters with trunks of more than 1.5 meters in diameter. Additionally to their extraordinary size, some form enormous roots that open up at their base in a triangle shape; thes include the ceibos, sangres de gallina, and canelos. Other species, of equal or lesser size, grow from these singular roots, such as sangres de drago, cruz caspi, chunchos, and cacaos de monte.Settled amonst these huge trees you'll find a vast range of palm species. Also abundant are chontas, chambrias, ungurahuas, and pambiles.
Yasuni is home to 12 monkey species, ranging from the larger ones such as spider, wooly and howling monkeys, to the smallest in the world that is the leoncillo or mono de bolsillo (pocket monkey). We also have the chichicos bebeleche, named this way because of their habit to suck the sap of certain trees. Other mammals include jaguar, the largest feline in America, and capybara, the largest rodent in the world. There are also pumas, Amazon tapires, ant-eaters, wild boar, and smaller mammals such as deer, tigrillos, guatines, and cusumbos. 
The birds are another spectacular group. In large flocks the colorful guacamayos and parrots cross the skies. Among the plant foliage the tucans, sigchas, fly-eaters, woodpeckers, nuthatches, and a variety of hummingbirds. We also find trompeteros and tinamues walking on the ground. On the branches of the shrubbery and of vegetation we find arboreal frogs of an intense green color and with huge eyes; underneath leaves and rocks of the ground, there are the tiny nursing frogs that care for their eggs. On the rivers and lagoons, such as Añangu and Tabococha, live the pink dolphings, small gray dolphins, manatees and giant otters. Close to the water there is an infinity of herons, hoatzines, and cormorants, as well as the charapas turtles. In the rivers you can also observe the giant anaconda and a great variety of fish such as cachamas, paiches, palometas, bocachicos, catfish, shad, and tucanaris.