Another interesting specimen on display at Seattle’s Burke Museum of Natural History and Culture:
In particular, this is an example of Paraphysornis brasiliensis, a 22 million year old South American “terror bird.” These interesting creatures originated on the continent some 60 million years ago, when it was an island and so isolated from other land masses and their fauna. Lacking other apex predators to contend with, the group diversified to become the dominant predators in South America for much of the Cenozoic. Some species reached three meters (10 feet) in height, while this one stood a more modest two meters (six feet) and weighed about 180 kg (400 pounds).
About 2.5 million years ago, the Isthmus of Panama bridged North and South America, allowing land animals to pass between them. North America became a new home to migrating terror birds (ranging into modern-day Florida and Texas), while sabre-toothed cats expanded into South America. In the end, the cats won and the terror birds went extinct.