What Does it Eat?

 The simple answer to the question "What does Phorusrhacos eat?" is pretty much anything smaller than itself that it could chase down or surprise. However, we could instead scour the literature and time scales and create a much more definitive and accurate list as well, if one were so inclined. Knowing that Phorusrhacos is well represented in the Santacrucian South American Land Mammal Age, I think that looking at the group of animals that are known and of a size that they could have been prey is a little more informative than making a giant pile of South American fauna. In popular venues (like BBC's Walking with Beasts) Phorusrhacos is shown attacking Smilodon cubs, Macrauchenia (as a scavenger), and smaller animals like Diadiaphorous. The majority of the animals that Phorusrhacos attacks in popular culture shows are pure imagination because they were not contemporaneous with the large bird. Of the three mentioned, Diadiaphorous is the only likely prey item because it did live at the same time. Necrolestes (possibly a mole-like creature), Cladosictis (a small marsupial carnivore), and Peltephilus (a genus of canine-sized armadillos) could have also been on the menu for Phorusrhacos. "Anything smaller" could have included other terror birds, like Patagornis and Psilopterus, other birds in general (Liptornis and Thegornis, for example), and the young of large ungulates (like Nesodon), ground sloths (like Pelecyodon), and Astrapotheres (large animals that looked like elephants or tapirs). While images of Phorusrhacos like the one show here are really intriguing, Glyptodon would not have been on the menu either, as it was a Plesitocene mammal, and Phorusrhacos was long gone by the time it came around.