Baluchitherium was an early hornless rhinoceros which lived in Asia and fed on tree leaves during the late Oligocene (38 to 24 million years ago ) and early Miocene (24 to 5 million years ago). It was the largest known land mammal to have lived, estimated to be 18 feet tall at the shoulder, 33 feet long and weighing more than 20 tons.
Uintatherium laticeps, “Beast of the Uinta Mountains” was a mammal that lived during the Eocene epoch beginning around 52 million years ago. Uintatherium fossils were discovered near the Uinta Mountains in Wyoming and in Utah.
Uintatherium was a herbivore that could grow to 13 feet long, almost 6 feet tall and weigh more than 4,000 lbs. It had robust pillar like legs similar to a rhinoceros. Its most unusual feature was the protruding knobs on its snout and brow. It had a thick, oddly shaped skull, with downward pointing canines somewhat similar to saber-toothed tigers, but was not carnivorous and the canines must have been for defense.
Titanotheres and Tortoises
Titanotheres, or Brontotheres were hoofed mammals that lived between 56 and 34 million years ago during which some species evolved to have huge bulky body sizes up to 8 feet in height with with strong, pillar-like limbs, massive skulls, and bizarre hornlike skull appendages. Their remains are numerous providing clear records of varying forms.
Dinoceras anceps, formerly known as Dinoceras mirabile were mammals that lived during the early Eocene 52 million years ago in the areas of Utah and Wyoming. They were herbivores that grew to 7 1/2 ft tall, 13 ft long, and weighed 2 1/4 tons. An exceptionally thick skull left a small cranial cavity for brains.
Arsinoitherium are related to elephant species. These extinct mammals were rhinoceros-like herbivores that lived during the late Eocene and the early Oligocene of northern Africa from 36 to 30 million years ago in areas of tropical rainforests and mangrove swamps. They stood 5 feet tall at the shoulders, were 10 feet long and weighed more than 2 1/2 tons. Their enormous horns were solid bone.
Archelon, Archelon ischyros
The Giant Turtle Archelon was a slow moving creature of the ancient seas during the Cretaceous (146 to 65 million years ago). Some remains measure over 15 feet long. Like many of today’s turtles it ate jellyfish and expired drifting fish as well as plants, buried its eggs in sandy beaches, and may have lived more than 100 years.
This 120 million year old fossilized skeleton of an Archelon next to a standing man gives a perspective of the size of these giant turtles
Meganeura monyi, Giant Dragonfly
Meganeura monyi is a genus of extinct insects from the Carboniferous period approximately 300 million years ago. They are related to present-day dragonflies and had a 29 inch wingspan. They fed on other insects, and even small amphibians. M. monyi is one of the largest known flying insect species ever.
The Giant Kangaroos
Giant Kangaroos, Procoptodon goliah, as large 9 feet tall and weighing 500 lbs once lived in Australia during the Pleistocene epoch as recently as 40,000 to 20,000 years ago before going extinct, possibly due to human influence.
Giant Ground Sloth
The Giant Ground Sloth, Megatherium americanum, was 18 feet long, as big as an elephant, and lived in South America during the Pleistocene until just a few thousand years ago. Other species from the size of a cat to that of the the giant ground sloth lived from the Arctic to Antarctica. They were hunted by humans and some believe humans may even have farmed them.
Giant Early Shark, Megalodon
Megalodon was a prehistoric shark that lived roughly from 28 to 1.5 million years ago, during the late Oligocene to early Pleistocene periods. Estimated to have been over 50 feet long it was one of the largest and most powerful vertebrate predators ever to have lived.
Giant Australian Marsupial Diprotodon
The Giant Australian Marsupial, Diprotodon, looked like and sometimes referred to as a giant Wombat and lived from 1,600,000 to 40,000 years ago during the Pleistocene. It was the largest marsupial that ever lived, the size of a hippopotamus, 9 feet long and 6 feet high at the shoulders. It probably ate tree leaves, shrubs and grasses.
THE BIRD GIANTS
The Great Toothed Diver
These extinct 9 ft Tall, 280 lb flightless, carnivorous “Terror Birds” lived In Patagonia during the Pleistocene era. Phororhacos longissimus, one of the largest carnivorous birds to have ever to have lived, had claws like meat hooks and a massive hooked beak for ripping flesh from its prey while holding them down with sharp talons.
One of the largest flying birds ever lived in Argentina during the Miocene. It had a wingspan of 23′ and weighed as much as 150 lbs. It is related to the Andean Condor.
Great Toothed Diver, Hesperornis regalis
The Great Toothed Diver, Hesperornis regalis, an extinct five foot long diving bird lived during the Cretaceous period – with teeth! H. regalis did not have wings, but propelled itself with powrful hind legs and lobed toes similar to the grebes of today. It lived in the prehistoric North Sea, the West Siberian Sea, and the Great American Inland Sea, preyed upon fish, crustaceans, cephalopods and mollusks and were preyed upon by Mosasaurs.
12 Foot Elephant Birds
Enormous ostrich-like birds of Madagascar standing as tall as twelve feet and weighing more than 800 pounds have been extinct since the 17th century.
Aepyornis maximus, which weighed close to 900 lbs are one of the subspecies of the Elephant Birds of Madagascar.
The largest of the giant flightless land birds called Moas of the savannahs and forest fringes of New Zealand and surrounding islands stood as tall as 13 feet. Hunting by the Maori may have driven them to extinction shortly before Europeans arrived.
Another of the subspecies in the Moa family of New Zealand. We know from remains it was covered with reddish-brown hair-like feathers, may have stood as high as 12 feet and weighed more than 600 pounds.
Diatryma were another large bird which you would not have been able to outrun, however, it is uncertain whether they were herbivores or carnivores. But with that beak you would run regardless. It may have been used to crack nuts or to rip flesh. They grew to 6 feet tall and weighed more than 200 lbs. They lived about 60 million years ago in North America and Europe