The Great American Interchange was a very important paleozoogeographic event in which land and freshwater animal faunas migrated from Central America to South America and vice versa, as the volcanic Isthmus of Panama rose up from the sea floor and bridged the continents. The migration peaked dramatically around 3 Million years ago (Piacenzian, the first half of the Upper Pliocene). Phyla Porifera (sponges) Ctenophora (comb jellies) Cnidaria (coral, jellyfish, anenomes) Placozoa (trichoplax) Subregnum Bilateria (bilateral symmetry) Acoelomorpha (basal) Orthonectida (flatworms, echinoderms, etc. ... Fauna is a collective term for animal life. ... Migration occurs when living things move from one biome to another. ... Commonly, Central America is the region of North America located between the southern border of Mexico and the northwest border of Colombia, in South America. ... South America South America is a continent crossed by the equator, with most of its area in the Southern Hemisphere. ... The Isthmus of Panama is the narrow strip of land between the Caribbean Sea and Pacific Ocean which links North America and South America. ... Dymaxion map by Buckminster Fuller shows land mass with minimal distortion as only one continuous continent A continent (Latin continere, to hold together) is a large continuous land mass. ... Mega-annum, usually abbreviated as Ma, is a unit of time equal to one million years. ... In the geologic timescale, Piacenzian is an ICS stage, part of the Pliocene epoch of the Neogene period. ... The Pliocene epoch (formerly Pleiocene) is the period in the geologic timescale that extends from 5. ...

It resulted in the joining of the Neotropic (roughly South America) and Nearctic (roughly North America) definitively to form the Americas. The interchange is visible from observation of both stratigraphy and nature (neontology). Its most dramatic effect is on the zoogeography of mammals but it also gave an opportunity for non-flying arthropods, reptiles, amphibians and even freshwater fish to migrate. The Neotropic ecozone is a terrestrial ecoregion which includes South America, Central America, and the Caribbean. ... The Nearctic is one of the eight terrestrial ecozones dividing the Earths land surface. ... World map showing America CIA map of the Americas (as it is now known in English) The Americas commonly refers to the landmass in the Western Hemisphere consisting of the continents of North America and South America with their associated islands. ... Stratigraphy, a branch of geology, is basically the study of rock layers and layering (stratification). ... Neontology is the part of biology which – in contrast to paleontology – deals with now living (recent) organisms. ... Zoogeography – is the branch of the science of biogeography that is concerned with the geographic distribution of animal species. ... Subphyla and Classes Subphylum Trilobitomorpha Trilobita - Trilobites (extinct) Subphylum Chelicerata Arachnida - Spiders, Scorpions, etc. ... Orders  Crocodilia - Crocodilians  Rhynchocephalia - Tuataras  Squamata   Suborder Sauria- Lizards   Suborder Serpentes - Snakes   Suborder Amphisbaenia - Worm lizards Testudines - Turtles Superorder Dinosauria  Saurischia  Ornithischia Reptiles are tetrapods, and also are amniotes, animals whose embryos are surrounded by an amniotic membrane. ... Orders Subclass Labyrinthodontia - extinct Subclass Lepospondyli - extinct Subclass Lissamphibia   Anura   Caudata   Gymnophiona Amphibians (class Amphibia) are a taxon of animals that include all tetrapods (four-legged vertebrates) that do not have amniotic eggs. ... Groups Conodonta Hyperoartia Petromyzontidae (lampreys) Pteraspidomorphi (early jawless fish) Thelodonti Anaspida Cephalaspidomorphi (early jawless fish) Galeaspida Pituriaspida Osteostraci Gnathostomata (jawed vertebrates) Placodermi Chondrichthyes (cartilaginous fish) Acanthodii Osteichthyes (bony fish) Actinopterygii (ray-finned fish) Sarcopterygii (lobe-finned fish) Actinistia (coelacanths) Dipnoi (lungfish) A fish is a poikilothermic (cold-blooded) water-dwelling...

South America was characterised by a strange endemic fauna, consisting only of xenarthrans, notoungulates (the "alternative ungulates"), litopterns and marsupials, like armadillos, sloths (like the giant ground sloth, Megatherium) and anteaters. The marsupials present in South America were didelphimorphs (opossums and relatives), but many larger forms also existed, like the Miocene saber-toothed marsupial Thylacosmilus and the borhyaenids. The notoungulates and the litopterns occupied ungulate ecological niches and had many strange forms, like Macrauchenia, a litoptern with a small proboscis. Both groups started evolving in the Lower Paleocene, possibly from condylarth stock, diversified, dwindled before the great interchange, and went extinct in the Pleistocene. In biology and ecology endemic means exclusively native to a place or biota, in contrast to cosmopolitan or one of various ways of being not native (e. ... Families Myrmecophagidae Megalonychidae Bradypodidae Dasypodidae The order Xenarthra is a group of placental mammals, extant today only in the Americas. ... Llamas such as this, which have two toes, are artiodactylas -- even toed ungulates Ungulates (meaning roughly hoofed or hoofed animal) make up several orders of mammals, of which six to eight survive. ... The Litopterna, also known as the pseudo-horse, is an order of fossil mammals from the Tertiary Period that displays toe reduction. ... Orders Superorder Ameridelphia Didelphimorphia Paucituberculata Superorder Australidelphia Microbiotheria Dasyuromorphia Peramelemorphia Notoryctemorphia Diprotodontia Marsupials are mammals in which the female typically has a pouch (called the marsupium, from which the name Marsupial derives) in which it rears its young through early infancy. ... Genera Chlamyphorus Cabassous Chaetophractus Dasypus Euphractus Priodontes Tolypeutes Zaedyus This page is about the animal. ... Families Megalonychidae P.Gervais, 1855 Bradypodidae Gray, 1821 Sloths are medium-sized South American mammals belonging to the families Megalonychidae and Bradypodidae, part of the order Xenarthra. ... Families Rathymotheriidae Scelidotheriidae Mylodontidae Orophodontidae Megalonychidae Megatheriidae Ground sloths are extinct edentate (Order Xenarthra) mammals that are believed to be relatives of tree sloths and three-toed sloths. ... Genera Myrmecophaga Tamandua Cyclopes Anteaters are mammals of the order Xenarthra and the family Myrmecophagidae, commonly known for eating ants and termites. ... Genera Several; see text Opossum fur is quite soft, and was once commonly used in coats. ... The Miocene epoch is a period of time that extends from about 23 to 5. ... This article needs to be cleaned up to conform to a higher standard of quality. ... In ecology, a niche is a term describing the relational position of a species or population in an ecosystem. ... Macrauchenia waas a long-necked and long-limbed, three-toed South American ungulate mammal, typifying the suborder Litopterna (q. ... In general, a proboscis (from Greek pro before and baskein to feed) is an elongated appendage from the head of an animal. ... The Paleocene epoch (65-56 MYA) (early dawn of the recent) is the first geologic epoch of the Palaeogene period in the modern Cenozoic era. ... Condylarthra is an order of Paleocene mammals. ... The Pleistocene Epoch is part of the geologic timescale. ...

The North American fauna was a pretty typical boreoeutherian one.

The interchange already started around 30 Mya (late Oligocene), when rodents started invading South America through island-hopping and (at least one fertilised female, more commonly a group of animals) accidentally "rafting" (on driftwood for instance) southwards or northwards. Rodents gave – among others – rise to capybaras, chinchillas and viscachas. A little later primates followed. The primates capable of migrating had to be small. These gave rise to the New World monkeys (Platyrrhini). The Oligocene epoch is a geologic period of time that extends from about 34 million to 23 million years before the present. ... Families See Classification Section The order Rodentia is the most numerous of all the branches on the mammal family tree. ... Island hopping refers to crossing an ocean by a series of shorter journeys between islands, as opposed to a single journey directly across the ocean to the destination. ... [[{{{diversity_link}}}|Diversity]] {{{diversity}}} Binomial name Hydrochoerus hydrochaeris (Linnaeus, 1766) Trinomial name {{{trinomial}}} Type Species {{{type_species}}} {{{subdivision_ranks}}} Capybara range Synonyms {{{synonyms}}} The capybara (Hydrochoerus hydrochaeris) is the largest of living rodents (the long-extinct Phoberomys pattersoni was significantly bigger). ... Genera  Chinchilla  Lagidium  Lagostomus Chinchillas and their relatives viscachas are small, nocturnal mammals native to the Andes mountains in South America and belonging to the family Chinchillidae. ... Genera  Lagidium  Lagostomus The viscacha or vizcacha is a rodent of the chinchilla family Chinchillidae. ... [[{{{diversity_link}}}|Diversity]] {{{diversity}}} Binomial name {{{binomial}}} Trinomial name {{{trinomial}}} Type Species {{{type_species}}} Families * 15, See classification [[Image:{{{range_map}}}|{{{range_map_width}}}|]] Synonyms {{{synonyms}}} A primate is any member of the biological order Primates, the group that contains all lemurs, monkeys, apes, and humans. ... Families Cebidae Nyctipithecidae Pitheciidae Atelidae The New World monkeys or Platyrrhines are the four families of primates that are found in Central and South America, the Cebidae, Nyctipithecidae, Pitheciidae and Atelidae. ...

Around 7 Mya, raccoons invaded South America. Type species Ursus lotor Linnaeus, 1758 Species Procyon cancrivorus Procyon insularis Procyon lotor Raccoons are mammals native to the Americas in the genus Procyon of the Procyonidae family. ...

The last and most conspicuous wave, the great interchange, around 3 Mya, caused the immigration of llamas (also ungulates), mastodons, tapirs, felines (like pumas and saber-toothed cats), canids, bears and horses. Binomial name Lama glama (Linnaeus, 1758) The llama (Lama glama) is a large camelid that originated in North America and then later on moved on to South America. ... A Mastodon skeleton in museum in Bismarck, North Dakota. ... Species Tapirus bairdii Tapirus indicus Tapirus pinchaque Tapirus terrestris Tapirus yanivicus The tapirs are large, browsing animals, roughly pig-like in shape but with a short, prehensile trunk. ... Subfamilies Felinae Pantherinae Acinonychinae Machairodontinae (extinct) All cats are members of the family Felidae. ... Binomial name Puma concolor (Linnaeus, 1771) The puma (Puma concolor since 1993, previously Felis concolor) is a type of predator-feline found in North, Central, and South America. ... Tribes Metailurini Homotheriini Smilodontini Machairodontinae is a subfamily of the Felidae (true cats). ... Genera Alopex Atelocynus Canis Cerdocyon Chrysocyon Cuon Dusicyon Fennecus Lycalopex Lycaon Nyctereutes Otocyon Pseudalopex Speothos Urocyon Vulpes Canidae is the family of carnivorous and omnivorous mammals commonly known as canines. ... Genera Ailuropoda Ursus Tremarctos Arctodus (extinct) A bear is a large mammal of the order Carnivora, family Ursidae. ... Binomial name Equus caballus Linnaeus, 1758 The Horse (Equus caballus) is a sizeable ungulate mammal, one of the ten modern species of the genus Equus. ...

In general, the net migration was symmetrical. Later on, however, the Neotropic species proved far less successful than the Nearctic, witness the relatively low number of xenarthrans and marsupials in North America. This "bad luck" happened both ways: northwardly migrating animals were not able to compete for resources as well as the Nearctic species already occupying the same ecological niches. The southwardly migrating boreoeutherians are thought to have caused the extinction of some of the South American mammals. The presence of armadillos and opossums in the United States is explained by the Great American Interchange. Opossums were by far the most successful northward migrants, reaching as far as Canada. Generally speaking, however, the rodents' dispersal and consequent adaptive radiation through South America was much more successful (both spatially and by number of species). In biology and ecology, extinction is the ceasing of existence of a species or group of taxa. ... Adaptive radiation describes the rapid speciation of a single or a few species to fill many ecological niches. ...

South American Species that Migrated North...

• Porcupines
• Capybaras...for a time
• Armadillos
• Ground Sloths
• Gyptodons
• Opossums

Genera Family Erethizontidae   Coendou   Sphiggurus   Erethizon   Echinoprocta   Chaetomys Family Hystricidae   Atherurus   Hystrix   Thecurus   Trichys Porcupines are rodents best known for their coat of sharp spines, or quills, that defend them from predators. ... Genera Chlamyphorus Cabassous Chaetophractus Dasypus Euphractus Priodontes Tolypeutes Zaedyus This page is about the animal. ... Families Rathymotheriidae Scelidotheriidae Mylodontidae Orophodontidae Megalonychidae Megatheriidae Ground sloths are extinct edentate (Order Xenarthra) mammals that are believed to be relatives of tree sloths and three-toed sloths. ... This article or section should be merged with Virginia_opossum The word opossum (usually pronounced without the leading O, or with only a very slight schwa) refers either to the Virginia Opossum in particular, or more generally to any of the other marsupials of magnorder Ameridelphia. ...

North American Species that Migrated South...

• Llamas
• Tapirs
• Deer
• Mice and Rats
• Skunks
• Mustelids such as grisons
• Foxes
• Horses...for a time
• Elephants...for a time
• Raccoons

Binomial name Lama glama (Linnaeus, 1758) The llama (Lama glama) is a large camelid that originated in North America and then later on moved on to South America. ... Species Tapirus bairdii Tapirus indicus Tapirus pinchaque Tapirus terrestris Tapirus yanivicus The tapirs are large, browsing animals, roughly pig-like in shape but with a short, prehensile trunk. ... Subfamilies Capreolinae Cervinae Hydropotinae Muntiacinae A deer is a ruminant mammal belonging to the family Cervidae. ... Subfamilies See text Muridae is the largest family of mammals. ... Genera Conepatus Mydaus Mephitis Spilogale Skunks are medium-sized mammals with black-and-white-fur belonging to the family Mephitidae and the order Carnivora. ... The hurón or grison (Spanish: ferret) refers to either of two related ferret-like mammals from Central and South America: Galictis vittatus. ... A fox is a member of any of 27 species of small omnivorous canids. ... Binomial name Equus caballus Linnaeus, 1758 The Horse (Equus caballus) is a sizeable ungulate mammal, one of the ten modern species of the genus Equus. ... Genera and Species Loxodonta Loxodonta cyclotis Loxodonta africana Elephas Elephas maximus Elephas recki † Stegodon † Mammuthus † Elephantidae (the elephants) is a family of animals, and the only remaining family in the order Proboscidea. ... Type species Ursus lotor Linnaeus, 1758 Species Procyon cancrivorus Procyon insularis Procyon lotor Raccoons are mammals native to the Americas in the genus Procyon of the Procyonidae family. ...

External links

• History of the Fauna of Latin America by George Gaylord Simpson (1950)