Animals from South America and North America crossed paths as plates collided

Our story begins 65 million years ago, the beginning of the age of mammals,when what is now North and South America were continents separated by a marine connection between the Pacific and Atlantic Oceans. During this time, South Americawas the home of fauna that included armored glyptodonts as large as compact cars,giant ground sloths weighing more than a ton, opossums, monkeys, and carnivorous terror birds. North America had its own species, such as horses, bears, and saber-toothed cats. Over 20 million years, the shifting of the Farallon and Caribbean Plates produced the Central America Volcanic Arc, a peninsula connected to North America, with only a very narrow seaway separating it from South America.