Argentina -- Unsurprisingly, with such a large variety of ecosystems, Argentina has a huge range of flora and fauna. One of the most spectacular spots for wildlife watching is Esteros de Ibera, a vast wetland south of Iguazú where hundreds of species of birds compete with caiman and swamp deer for your attention. Guanaco and vicuña populate the arid Andes, while big cats like puma and jaguar are not unknown. Patagonia is more famous for its coastal wildlife, including sea lions, elephant seals, and whales. There are many species of trees; even the western deserts host two small squat specimens known as algorroba and quebracha, as well as huge three-fingered cacti. To the humid north you'll find carob and monkey puzzle trees; in the pampas, vast grasslands; and in El Chaco, you'll find a mixture of forest and savanna.

Bolivia -- Owing to Bolivia's drastic changes in altitude, the country has a diverse range of flora -- from high altitude shrubbery to green Amazonian rainforest. The desertlike Altiplano is limited to cacti and Ichu, a coarse grass that grows only above 3,500m (11,480 ft.). On the shores of Lake Titicaca plants like tortora reeds, famously used in the construction of the Uros islands, can be found. In the tropical regions in the country's north and east, there's an explosion of diversity in the form of hardwoods, fruits, vegetables, orchids, and Pará rubber trees.

Also owing much to the great divide in altitude, the country's fauna is equally diverse. In the Altiplano, South American camelids such as alpacas, llamas, and vicuñas play prominent roles, as do majestic condors, adorable vicachas, proud pumas, sly Andean foxes, and in the southwest, thousands upon thousands of feeding James, Andean, and Chilean flamingos.

In the north and east, the low-lying tropical forests and Pantanal are home to a wide range of rare species such as caimans, giant river otters, jaguars, spectacled bears, tapirs, and numerous species of monkeys. The bird life is remarkable here, with one of the highest levels of biodiversity on the planet. In protected areas such as Noel Kempff, Amboró, and Madidi national parks you might encounter macaws, herons, toucans, hummingbirds, the Cock of the Rock, and thousands of other species.

Brazil -- The golden lion tamarin -- a beautiful squirrel-size primate -- is the signature species of Brazil's Atlantic ecosystem, now much endangered. Common tamarins can often be seen in trees and parks in Rio. The coast is also the only place you'll find truly significant mountains. Inland, Brazil rises to a high plateau of from 1,000m to 1,500m (3,280-4,920 ft.) in altitude that rolls all the way to the western foothills of the Andes. In the southern parts of Brazil (Paraná, Santa Catarina, Rio Grande do Sul), this plateau was covered in subtropical rainforest, most of which has long since been converted to cropland. In the center and center west where things are drier (Goiania, Brasília, Mato Grosso do Sul, Mato Grosso, Tocantins), you'll find cerrado, dry scrubland forest reminiscent of California chaparral, dotted with beautiful branching Ipe trees -- known for bright yellow or purple flowers. Farther west still, on the Paraguay river basin that forms the border with Bolivia, stands the Pantanal. This world's biggest wetland (about the size of Florida) is actually a seasonal flood plain that fills and then slowly drains in response to seasonal rains. It is home to a rich assortment of birdlife -- jabiru storks, American woodstorks, red and hyacinth macaws -- plus capybara, giant otters, anteaters, and caiman. In the north, the semidesert inland from the coast is known as sertão. This is cowboy country, with cattle, bandits (historically), cactus, and not much else.

In the north, covering about a third of the country (Amazonas, Acre, Mato Grosso, Para, Roraima), stands the Amazon rainforest, the richest assortment of plants and animals on earth. Deforestation rates have been reduced in recent years, though a chunk the size of Connecticut still falls to the chainsaw every year.

Chile -- Chile's climatic and topographical features correspond to defined botanical regions that boast a rich diversity of flora. Ethereal Atacama, which extends from the far north into Bolivia, is a desolate, lunar landscape where at higher altitudes cacti provide the only vegetation. In the central regions, greater rainfall and a humid environment produce shrubbery and trees with leaves known as sclerohyllous ("hard" leaves that facilitate a greater absorption of water). Predominant tree species include the guayacan, litre, lun, and peumo. The Central Valley is also characterized by hard espinos, a species of cactus, as well as the endangered Chilean palm.

Desert brush lands sweep the Altiplano (a high Andean plateau comprised of basins), which yield to more verdant grasslands on the lower slopes of the Andes. In the region south of the Bío-Bío River, temperate rainforests with high precipitation have yielded over 45 species of endemic trees. Magnolias, laurels, oaks, conifers, and beeches thrive in the dense forests here, but perhaps the most striking is the distinctive monkey puzzle tree (araucaria), Chile's national tree.

Colombia -- Colombia's bird diversity is second only to Brazil, with over 1,800 species. It is the second-most biodiverse country in the world in terms of species per square mile, and is home to 10% of the world's species. The Amazon region and its rivers feature some of the world's strangest animals and marine life, such as the elusive pink dolphin. Tapirs, pumas, monkeys, wild boars, and caimans are among some of the jungle creatures visitors might spot.

Pine vegetation characterizes the high Andes, while low-lying areas are characterized by tropical vegetation. Colombia is home to over 50,000 plant species, most found in the dense jungle areas in the eastern and Pacific regions of the country.

Ecuador -- The biodiversity found within Ecuador's borders is stunning. While it only makes up .02% of the world's landmass, it contains an amazing 10% of the world's plant species. In fact, Conservation International has listed Ecuador as one of just 17 "megadiverse" countries on the planet. Cataloguing of the nation's biological treasures is far from complete, and already scientists have counted 3,800 species of vertebrates, 1,550 species of birds, 320 species of mammals, 350 species of reptiles, 375 species of amphibians, 800 species of freshwater fish, and 450 species of marine fish. Ecuador is a bird-watcher's paradise: A full 18% of the world's bird species can be found in Ecuador, more bird species per square meter than in any other Latin American country. In fact, although Brazil is 30 times Ecuador's size, Ecuador has just as many species of birds. And last but not least, there are over a million species of insects in Ecuador (they're not all ugly -- 6,000 species are butterflies).

Paraguay -- Rampant deforestation has caused Paraguay to lose much of its wildlife habitat, and native animals like jaguars, deer, giant anteaters, and giant armadillos are now endangered species. In the country's many rivers you'll still find crocodiles, piranhas, and boa constrictors. Plant life includes many types of hardwoods, especially ceiba and quebracho. The Chaco region to the west is made up of scrub and thorn forest.

Peru -- Nearly two-thirds of Peru is jungle, and many naturalists and biologists believe that Peru's Amazon rainforest holds the greatest diversity in the world. It teems with a staggering roster of wildlife: 400 species of mammals, 2,000 species of fish, 300 reptiles, 1,800 birds, and more than 50,000 plants. The country counts 84 of 103 existing ecosystems and 28 of the 32 climates on the planet among its remarkable statistics. Recent studies have shown that a region just south of Iquitos has the highest concentration of mammals anywhere in the world. Peru's other significant fauna are the great Andean condors, found principally in Colca Canyon, near Arequipa, and the rich marine life of the Paracas National Reserve and Islas Ballestas (Peru's version of the Galápagos Islands), home to communities of endangered Humboldt penguins and sea turtles, sea lions, red boobies, and flamingoes. Coastal Peru south of Lima is also home to one of the greatest population densities of dolphins in the world, with one-third of the world's species identified.

Uruguay -- Large wild animals have disappeared from the eastern regions of Uruguay. Foxes, deer, and otters can still be seen in the northern hills, while birdlife such as rheas, swans, and ducks can be found in the pampas and the central and northern lakes. Many indigenous hardwoods such as lapacho and quebracho have given way to introduced plant species such as eucalyptus and acacia.

Venezuela -- Thanks to its large and varied terrain, Venezuela has a stunning wealth of biodiversity. Bird-watchers will enjoy knocking many of the country's 1,200 species off their life lists. Of the most coveted species to spot here are the Andean condor, macaw, several toucan and parrot species, and the hoatzin, a strange and foul-smelling resident of the lowland plains. Meanwhile, over 325 mammals have been recorded, the most spectacular of which include the jaguar, capybara, manatee, and two distinct species of fresh water dolphin. The low, flooded plains of Los Llanos are a prime wildlife viewing spot, where you can see hundreds of bird species, as well as caiman, anaconda, and immense herds of capybara -- the world's largest rodent.

With ecosystems that range from tropical lowland rainforest to high Andean paramo, with almost every conceivable permutation in between, Venezuela's flora is abundant and diverse. Thousands of orchid species can be found across the country, and dedicated naturalists will want to visit the Gran Sabana, where a host of endemic species can be found, including many specific to a particular tepui. In the lowland rainforests, large trees like the ceiba can grow as tall as 40m (130ft). Meanwhile, its branches are home to hundreds of species of bromeliads, orchids, and assorted other epiphytes.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.