Arsinoitherium is an extinct genus of paenungulate mammal related to elephants, and hyraxes (Embrithopoda). These species were rhinoceros-like herbivores that lived during the late Eocene and the early Oligocene, from 36 to 30 million years ago, in areas of tropical rainforest, and at the margin of swamps. When alive, it would have superficially resembled a rhinoceros, and have been about 1.8 metres (5.9 ft) tall at the shoulders, and 3 metres (9.8 ft) long. The most noticeable feature of Arsinoitherium was a pair of enormous knife-like horns with cores of solid bone that projected from above the nose, and a second pair of tiny, knob-like horns on top of the head, immediately behind the larger horns. The skeleton is robust but shows that it was descended from a cursorial (running) ancestor, and that the beast may have been able to run if it had to, like a modern elephant or rhinoceros. Its limb bones also suggest that the columnar legs of the living animal were elephant-like (especially since they ended in five-toed feet), rather than rhinoceros-like. Arsinoitherium's 44 primitive teeth suggest that it was a selective browser. The large size and hefty build of Arsinoitherium would have rendered it largely immune to predation.

The Megalodon, "big tooth" in Greek, was a giant shark that lived in prehistoric times during the late Oligocene epoch and Neogene period, approximately 25 to 1.5 million years ago, and was a super-predator. It was by far the largest and most powerful fish of its time and one of the biggest hypercarnivorous predators ever known with maximum size theorized to be around 20.3 metres (67 ft) in length and 103 metric tons (114 short tons) in weight. From scrutiny of its remains, scientists conclude that C. megalodon belongs to the order Lamniformes but its genus is disputed. Fossil evidence has revealed that C. megalodon had a cosmopolitan distribution and fed upon large marine animals.

Smilodon sometimes called sabre-toothed cat, is an extinct genus of large saber-toothed cats that lived between approximately 2.5 million to 10,000 years ago in North and South America. They are called "saber-toothed" for the extreme length of their maxillary canines. The La Brea tar pits in California trapped hundreds of Smilodon in the tar, possibly as they tried to feed on mammoths already trapped. The Natural History Museum of Los Angeles County has many of their complete skeletons. Despite the colloquial name of "saber-toothed tiger", Smilodon is not closely related to a tiger, which belongs to another subfamily, the Pantherinae; Smilodon is a member of the extinct subfamily Machairodontinae. Among the largest felids, the heaviest specimens of this massively built carnivore may have reached a body mass of up to 400 kg/880 pounds.