Back in Purussaurus’ days, 8 million years ago, that region was actually a vast inland sea teaming with crocodiles, gharials, fresh water whales, giant rodents and enormous turtles. They have boundless creativity, unforgettable characters, quotable lines, interesting stories, and catchy songs that will literally stick with me for the rest of my life. Compared to modern day felids, a Xenosmilus’ kill would probably be extremely bloody; so much in fact that it would probably not be shown in Animal Planet! Altered habitats, brought on by climate change, probably had much to do with it. However, unlike modern lions, the American lion may have been a solitary predator. Why did they go extinct while the gray wolf, brown bear, and cougar still survive today? Mesonyx; Whales Edit. May 13, 2020. dino6600. All Rights Reserved. Since we don’t know when exactly Xenosmilus became extinct, we can’t tell if humans ever met this cat, or fell prey to it. List25.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program Falense [GFDL or CC-BY-SA-3.0], via Wikimedia Commons. Obviously, the only thing in the sea big enough to feed Megalodon where whales, and indeed, the giant shark’s bite marks have been found in the fossil remains of whales all around the world. They were quite agile and could probably run quite fast, unlike the predators that came before them. Instead, it had bony plates which turned its mouth into a beak similar to that of a sea turtle. The remains of this enormous predator where found in Egypt in 1915, and the paleontologist who studied them was already convinced that it was bigger than T-Rex. Acrophyseter was the complete opposite; it was moderately sized, and didn’t feed on squid but rather on other marine mammals and even on sharks! This is a fairly well known prehistoric monster, but it is just so big and scary that it deserves to be in this list. : By Dantheman9758 [GFDL or CC-BY-SA-3.0], via Wikimedia Commons. With a wingspan of over 30 feet, Quetzalcoatlus was one of the largest flying animals of all time. As you could expect from its name, Utahraptor was discovered in the state of Utah. This allowed it to quickly get the jump on its prey with little time for reaction. If the movie Anaconda terrified you (and not because of J-Lo’s acting), you might want to skip this one. Thus, I give you my finalized cast, I honestly have no idea why I am making this list right now mostly because their is no special occasion for this (I guess I just feel really happy right now), but by now all of you know that I love animation of all shapes and sizes. Learn how the killer pig was an evolutionary success, despite its ... A scientific study into the physiological and sociological life of the Saber Tooth Cat. Today’s great white shark probably has some of the most nightmarish set of teeth in Nature, but its distant prehistoric relative Edestus was so scary that it would make the great white look almost cute. This is a fairly well known prehistoric monster, but it is just so big and scary that it deserves to be in this list. Robert Bruce Horsfall [Public domain], via Wikimedia Commons. It was a member of the Canidae or dog family, but whereas modern day canids are built for speed and endurance, Epicyon was built for brute strength, and had jaws so powerful that they could crush bone as if they were crackers!