The rainy seasons of April The Cenozoic Era:The Neogene

Land Bridges Bring Animals to New Lands

Sea levels were lower due to the effects of continental collision. The North and South Poles began to have ice caps. During the Neogene Period, the polar ice thickened and took up more space in the ocean. The new mountains trapped water as snow and ice. All of this ice formation caused sea levels to drop even more. The drop in sea levels opened up land bridges between continents. This allowed animals to migrate between continents.
South America moved to the north. By the Pliocene Epoch it merged with North America forming the Isthmus of Panama. Armadillos, porcupines, ground sloths and opossums migrated from South America to North America. Dogs, cats, bears, and horses from North America crossed into South America.