Numbers in millions of years ago signify when animals first originated in (turquoise) or immigrated into (other colors) North America.
Red X's over numbers signify when mammal groups went extinct in North America (though not necessarily in rest of world). Notice that rhinos entered North America from Asia 55 million years ago, and thrived here till their extinction 5 million years ago.
Turquoise dots signify mammal groups still extant (alive) in North America in the wild.
Pronghorn "antelope" is the only family of large mammal originating in North America that never spread into the rest of the world. They are unrelated to African true antelopes, which are bovids. Cheetah is the only genus of cat that ever originated in North America, from ancestral felids that immigrated here from Asia. The American cheetah's recent extinction (13,000 years ago) is the reason that Pronghorn antelope are the fastest running herbivores in the world, and why they still run 20 mph faster than their fastest living predator (wolves). Should we "bring back" the cheetah to the American west?
Between 3 and 5 million years ago, horses and camels spread into Asia (becoming zebras in Africa), before going extinct in their land of origin 13,000 years ago.
The Great American Interchange- Three million years ago, South America was joined to North America for the first time since dinosaurs roamed the land. At that time, llamas (members of the camel family) migrated into South America, before becoming extinct in their continent of origin. Deer, bears, wolves/foxes, various cats, peccaries, tapirs, raccoons, rabbits, and (temporarily) elephants and horses also migrated south. Whether by disease or competition, many of South America's original stock of large mammals soon went extinct. In turn, South American animals that expanded their range into North America included the possum, the porcupine, the armadillo, and various genera of ground sloths and armored glyptodonts.35 million years agotree frogs, toads, and whiptail lizards rafted into North America from South America. Meanwhile, Raven was flying in from Australia.
NOTE: Connie Barlow has used this chart and the ones below with kids and adults, in telling the 65 million year story of the North American continent. For playful ways to learn this story, see 4 different versions of the experiential process, "Coming Home to North America".
Click to view or download HIGH RESOLUTION, LARGE FORMAT PHOTOGRAPHS of the following four charts:
Left: Families of animals that originated in North America.
Right: Families of animals that originated in Eurasia and then spread into North America. Below: Raven originated in Australia; mastodons and mammoths originated in Africa.
Three million years ago, when the Isthmus of Panama rose and connected South America to North America for the first time since the Dinosaur Era, there was a great interchange of mammals between the continents. Tapirs, deer, cats (including the jaguar), members of the dog family, raccoons, llamas, peccaries, squirrels, and the sloth bear immigrated south. At the same time, expanding northward from their home of origin in South America were armadillos, porcupines, possums, glyptodonts, and giant ground sloths. (Thirty million years before that time, toads and tree frogs rafted north from South America to begin populating this continent.)
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