conservative estimates put its wingspan at and up, and it may have been as much as . The weight of the bird was estimated to have been around . Another form, "Teratornis" olsoni, was described from the Pleistocene of Cuba, but its affinities are not completely resolved; it might not be a teratorn at all, but has also been placed in its own genus, Oscaravis. There are also undescribed fossils from southwestern Ecuador. Taubatornis campbelli is the earliest known teratorn species, from the Late Oligocene or Early Miocene of the Tremembé Formation, Taubaté Basin, Brazil. Description and ecology Despite their size, there is little doubt that even the largest teratorns could fly. Visible marks of the attachments of contour feathers can be seen on Argentavis wing bones. This defies some earlier theories that modern condors, swans, and bustards represent the size limit for flying birds. The wing loading of Argentavis was relatively low for its size, a bit more than a turkey's, and if there were any significant wind present, the bird could probably get airborne merely by spreading its wings, just like modern albatrosses. South America during the Miocene probably featured strong and steady westerly winds, as the Andes were still forming and not yet very high. T. merriami was small enough (relatively speaking) to take off with a simple jump and a few flaps. The fingerbones are mostly fused as in all birds, but the former index finger has partially evolved into a wide shelf at least in T. merriami, and as condors have a similar adaptation, probably in other species, too. Wing length estimates vary considerably but more likely than not were at the upper end of the range, because this bone structure bears the load of the massive primaries. Studies on condor flight suggest that even the largest teratorns were capable of flight in normal conditions, as modern large soaring birds rarely flap their wings regardless of terrain. Traditionally, teratorns have been described as large scavengers, very much like oversized condors, owing to considerable similarity with condors. However, the long beaks and wide gapes of teratorns are more like the beaks of eagles and other actively predatory birds than those of vultures. Most likely teratorns swallowed their prey whole; Argentavis could technically swallow up to hare-sized animals in a single piece. Although they undoubtedly engaged in opportunistic scavenging, they seem to have been active predators most