Between the mountain peaks and above the valleys of the Andes soar a number of large birds and pterosaurs. They circle in the winds rising from the valley heads and the updrafts from warm hill slopes. One of the largest of these soaring creatures is the harridan, a pterosaur. It can maneuver expertly while in flight. The air sweeping over its broad wings is controlled by additional membranes attached to the second and third fingers of the hand. These two fingers are elongated but not as much as the fourth finger that in all pterosaurs, supports the main flying membrane. The first finger carries a claw which is used when the animal is crawling on cliff faces. Its head is almost mammal-like, with an elongated snout and sharp teeth at the front. The eyes are directed forward and give a good stereoscopic vision.
This pterosaur is a solitary animal. It mates for life and nests on high pinnacles in the mountains, rearing no more than two young each year. With its warm-blooded physiology, and its carnivorous hunting habits, it is very similar to the predatory birds that are found in the mountainous areas of other ecozones.
The harridan has very keen eyesight and can spot smaller animals scampering about on the ledges hundreds of meters below. It then swoops out of the sky and pounces accurately on its food. Its prey usually consists of the small mammals (placental eutherians and ameridelphian marsupials) that have adopted a mountain habitat. Sometimes it might go after a small non-avian dinosaur, such as a dip.