Phorusrhacos, the "Rag-Thief" or "Wrinkle Bearer," is a "terror bird" that is only known from partial fossils. Its approximate size is estimated to be two and a half meters tall, since with only fragmentary evidence its size cannot be said for certain. The meaning of its name describes the "wrinkled" curve of its lower jaw. Like other terror birds, it had a massive hooked beak that was built for consuming meat. How it hunted is unknown, but it almost certainly feasted on small mammals. It may have used its beak or sharp claws to deal blows on their unfortunate prey, or repeatedly beat their poor victims against the ground like their modern relatives seriemas. During the start of its reign in Miocene Argentina, Phorusrhacos ruled grasslands and woodlands, stalking around in the search for food around the hills that would eventually become the Andes Mountains. It lived alongside four other terror birds, so they must have evolved to hunt different prey - otherwise, they undoubtedly would have fought with one another. Although a fearsome predator, the Phorusrhacos went extinct before the Miocene Epoch ended, and at present it is not known why. Until further research is done or new fossils are discovered, it will continue to be another mystery paleontology is working to solve.