The rainforests of tropical South and Central America are the most species diverse ecosystems in the world.
The rainforest of the Neotropics covers a huge geographical area, from southern Brazil north to southern Mexico. Within that area, it also varies in form and species composition as it grows from sea-level in the lowlands of the Amazon, to the cloud forest in the Andes.
At the very limit of rainforest growth in the mountains, the trees grow stunted. The higher altitude rainforest has a lot of lichens and moss covering the trees. The forest is misty and quiet. As one travels down in altitude, the trees grow taller, and the ease of birding peaks at the mid-altitude rainforest.
A view from the cloud forest looking down into the rainforest of the mountains and valleys, on the Manu road from the top of the Andes down to the Amazon river.
Much of the rainforest in the lowlands of the Amazon is seasonally flooded. After heavy rain the overflow of water from the main rivers and tributaries creates several hundred thousand square kilometres of 'flooded forest'. These flooded forests represent between 3-4% of the Amazon basin. The water may rise up to 15 metres, and flow 20 kilometres in from the main rivers.
They are generally categorized into the Varzea and the Igapo. The former is created by the muddy waters of main white water rivers, the latter by the clearer 'black water'. The Varzea flooding comes and goes quickly, while the Igapo forest may remain flooded for half of the year. The former are nutrient rich waters, flowing from the Andes, and thus have higher productivity. The white water flooded Varzea also have higher diversity of species, while the black water Igapo floodplains are less diverse, dominated by a few species of Legume. On this website, these flooded forests overlap with the more open Neotropical freshwater wetlands.
The rainforests of tropical South and Central America have the highest diversity of plants in the world...
The most diverse family of plants in the world are the Orchids. In the tropical Americas, they are easiest to see in the cloud forest, at high altitude...
As with most tropical rainforests around the world (except south-east Asia), there are no species that dominate the rainforest canopy. Instead, there is a high diversity but low abundance of specific species. One of the notable families is the Malvaceae, which includes:
Other important families in the Neotropical forests are the Myrtaceae and Melastomataceae. In the latter family are many smaller forest and edge shrubs. There are over 1000 species of Miconia alone.
Another family of smaller shrubs is the Verbanaceae, which includes the ubiquitous 'Snake Weed'.
The arachnids include the spiders and scorpions. Of the spiders, the most infamous family in the Neotropics is the family Theraphosidae, which includes the true 'Tarantulas'. The are found throughout the tropics of the world, but seem most obvious, species rich and BIG in the neotropics. While there are tiny species, they are best known due to the large size and weight of many species. This size is reflected in their diet, with some species of tarantula being recorded to kill and eat reptiles, mice, bats and birds. They are not known to be deadly to humans, however, their bites can be painful.
In contrast, the Spiny-back Spiders are small but stunning spiders decorated with bright colours and spines.
Centipedes and millipedes are long with many legs. The main difference between the two groups is that centipedes appear to have one leg per segment (on either side), while millipedes appear to have two. Centipedes are usually fast movers, and often predate on other invertebrates, while millipedes are generally slower, and feed on decaying vegetation. The former can have painful bites, while the latter have chemical defences. Millipedes tend to roll into a defensive ball when touched; centipedes shouldn't be approached, closely touched, or insulted!
The rainforests of the tropical Americas have the highest diversity of insects in the world. It has been reported that you will find more species of ants on a single tree in a Neotropical rainforest than occur across the entire country of England.
The insects of this order Orthoptera include the Crickets & Katydids, and Grasshoppers. Generally, the nocturnal crickets are duller coloured, while the diurnal grasshoppers can be brighter colours; however, in the tropical rainforest crickets are often colourful bright greens. Their loud calls give away their presence.
The order Diptera includes the flies. The family Tachinidae includes over 8000 recorded species so far, and are found all over the world. They are particularly diverse in South America.
Beetles are similar to the true bugs in their rounded appearance and their hard protective forewings that fold over the softer hindwings. However, they differ in the fact that the wings usually meet straight in the middle (to form the protective elytra) and they have efficient biting rather than sucking parts. The elytra is often shiny and produces some beautiful colours and textures. This harder layer is lifted up when the hind wings are used for flight. The high number of species of beetles is famous amongst biologists, and they are usually considered the most diverse of all animal groups.
The great range of moths in the Neotropical rainforests can be appreciated by checking out the lighter coloured walls that are lit up in lodges at night: or even better, hang up a white sheet and light it up...
There is also a huge diversity of beautiful species in the rainforests across the tropical Americas. The biggest and showiest butterflies are the Swallowtails of the family Papilionidae.
Perhaps the most distinctive and recognisable of the Neotropical butterflies are the...
One of the more interesting groups are the 25 or so species of Hamadryas 'Cracker Butterflies'. They are usually spotted, and sometimes blend in when seen perched on trunks upside down. They get their common name from make a crackling sound during territorial displays. Unlike most other butterflies they don't feed on nectar from flowers, but are attracted to rotting fruit on the forest floor, sap and even animal dung.
Another distinctive and spectacular group are the 'Clearwings', with their stunning transparent wings.
Within the order Hymenoptera is the family Formicidae, which contains over 1000 species of ants in the Amazon region alone.
If you see a line of leaves walking up a tree, you are witnessing 'Leaf-cutter Ants' at work.
Frogs are amphibians without tails. And with those big eyes and floppy limbs and no teeth, they are so cute!
The family Hylidae incudes the classic tree frogs. As the name suggests, they are often found calling or climbing on branches in trees or bushes. Much of their morphology reflects this lifestyle; they are often green in colour, with long limbs for jumping, and large bulging eyes for judging distances. It is a large and widespread family across the tropics and warmer parts of the world, and they are split into several different sub-families that are sometimes treated at their own families, such as the Boana.
The (sub) family Phyllomedusidae includes the 'Leaf Frogs' and Phyllomedusa, the 'Monkey Frogs'.
The most familiar amphibian family to most pople, and the most widespread, is the family Bufonidae, the '(True) Toads'
The most famous amphibians within the Neotropical rainforest is no doubt those in the family Dendrobatidae: the 'Poison Arrow/Dart Frogs'. These frogs are usually small but stand out from the rainforest floor as they are often colourful. The poison arrow frogs are, as the common name suggests, toxic to eat. Thus, they walk around th forest floor in the daytime and in the open and not worried about being molested; unless a big human like me comes along. They are found in rainforests & associated habitats, only in South & Central America (although there is a sinmila looking group of frogs in Madagascar).
The Iguanids are the most obvious group of lizards in the Neotropical forests. The family Dactyloidae includes the Anole Lizards.
Another group of Iguanids are the Neoptropical Ground Lizards of the family Tropiduridae.
There are some large snakes in the Neotropical forests, such as the Boa Constrictors. Depending on taxonomy, there are five species. They are a lie-and-wait predator and strike and coil around their prey, cutting off blood circulation to their victim, then swallowing. They are found across the tropical parts of Central and South America.
However, the biggest snakes in the Neotropical forests are the infamous Anacondas.
Many of the smaller more commonly seen snakes belong to the family Colubidae.
The largest reptiles are the crocodilians. 'Black Caiman'. Growing up to 5 metres; thus it is considered to be the apex predator in lowland Amazonian rainforest.
The order Tinamiformes only contains the Tinamous. They are related to the rheas and other ratites. There are some 46 species, and they are only found in Central and South America.
The widespread family Anatidae that contains the ducks, geese and swans, includes a fascinating species in the higher altitude Neotropical waterways called the 'Torrent Duck': an unusual duck that has adapted to swimming and diving through the waters of fast flowing rivers.
Members of the family Cracidae (including Guans, Curassows, and Chachalaca) are often seen on the floor of the rainforest or perched on lower tree limbs on the edge.
There are over 350 species in the large Hummingbird family Trochilidae. They are known as 'hummingbirds' because of the relatively loud humming sound from the beating of their wings. When I first heard it, I thought it was a growl from a predatory mammal! The smaller species can flap their wings up to 80 times a second. They mostly drink nectar from flowers, although they also take insects and spiders to provide other nutrients. The forked tongue is used to lap up nectar. They spend about 10% of their time feeding, the rest of the time perching. They can detect the percentage of sugar in the nectar, and usually don't drink from flowers with less than 10% sugar in their nectar. They drink about half the body weight each day, more if the nectar has lower percentages of sugar; that is like a human drinking 35 litres.
This is a huge family of over 335 species, with many different distinct genera.
The name 'Colibri' is Espanol for 'hummingbird'. There are five species of 'Violet-Ears' and they are commonly seen. They are generally greenish, with colourful throat and ear patches, thus the common name.
There are 9 species in the genus Chrysuronia the 'Saphires'.
There are four species in this distinctive genus Calliphlox, the 'Woodstars'. They are small (even for hummingbirds) and fly like giant bumblebees.
The monotypic family Opisthocomidae includes just one species, the famous 'Hoatzin', a large bird with a blue face and messy crest that climbs about noisily in waterside trees clumsily, often stretching and grunting. Unlike most other birds, it is mostly a folivore. It is only found in swampy habitats in South America.
The Neotropical forests (and other more open habitats of the Americas) include large scavengers known as 'New World Vultures'.
One of the more spectacularly famous and colourful of birds in these forests are the Trogons. They sometimes sit motionless on branches, allowing some good photographs, if you can find them! They live in the rainforests of Africa, tropical Asia and the Neotropics.
There are many groups of colourful and strange Neotropical rainforest birds...
The family Capitonidae includes the 'New World Barbets' and the family Semnornithidae contains the 'Prong-billed' & 'Toucan Barbets'
And of course the most famous of the Neotropical rainforest frugivores, the Toucans. There are some 40 species in this family. They have usually medium to large sized birds, always with large bnills and bright colours. All species are all restricted to the Neotropics. Here, they are the New World equivalent to the Hornbills of the Old World tropics of Africa and Asia.
The largest family of birds in the world is the Family Tyrannidae, the Tyrant Flycatchers. All 436 species are endemic to the Americas.
The large family Furnariidae includes Neotropical Miners, Neotropical Leaf-tossers, Woodcreepers, Earthcreepers, Cinclodes, Foliage-cleaners, Spinetails, and many more...
Species in the Thrush family the Turdidae are commonly seen.
'American Sparrows' of the family Passerellidae small and common.
Some of the more loud and obvious birds are in the 'New World Blackbirds' the Family Icteridae, such as the Oropendolas.
Some birds, like the 'Summer Tanager' (a Cardinal, not a Tanager) are seasonal migrants from North America.
Tanagers are one of the most colourful and diverse group of birds in the Neotropical jungle. They are the second largest family of birds, with over 200 species. Many are colourful, and most are distinct enough to be easily recognisable. All the species in the Tanager are restricted to the Neotropics; many have small distributions.
The smallest primates are the Marmosets and Tamarins. They scamper about in cooperative polyandrous groups, with one central reproductively active female, who breeds with multiple males. They are reported to produce mostly twins at birth. They are only found in the Neotropics of South and Central America.
The family Cebidae contains some of the more commonly seen primates such as Capuchins and Squirrel Monkeys
The family Pitheciidae includes some of the more unusual looking and lesser known primates, such as Titi, Saki, and Uakari. Recent taxonomic classification studies has revealed there are many species of Titi Monkey, and they are endemic to small areas. They usually have brown, grey or reddish colours. Some species have a different coloured forehead or a unibrow. Unusually for primates, they mate for life. Poor buggers.
The diverse family Atelidae includes the iconic Howler, Spider & Woolly Monkeys
The squirrels of the family Sciuridae are common in the rainforest canopy, and some come down to visit feeders.
The Agoutis and Acouchis of the family family Dasyproctidae are mammals that are only found in South and Central America.
Big (and small) cats of the family Felidae are the major predators in many of the more pristine rainforest areas, however, they are seldom seen by the casual visitor.
There are so many great places (and lodges) to explore the rainforest in the tropical Americas...
In Colombia: Amacayacu National Park in the Amazon.