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10 Giant Ancestors of Modern Animals

While dinosaurs included some of the largest animals to have ever roamed the world, many animals have ancestors that were far larger than their modern relatives Although there were also many small prehistoric animals, including numerous dinosaur species, evolution does tend to produce larger animals over longer geological periods Following are 10 of the largest direct ancestors to common animals found today:

1. Paraceratherium

Paraceratherium was a type of hornless rhinoceros that lived between 34 and 23 million years ago across Eurasia. It was one of the largest land mammals in the world during its existence, boasting a weight of up to 20 tonnes and a height almost three times greater than a modern rhinoceros. Far larger than any elephant, the herbivorous beast was likelya herd animal and roamed the dunes and forests of what is now Central Asia and Siberia.

2. Castoroides

An extinct family of giant beavers, the castoroides grew to more than six feet long and weighed at least as much as an adult human. These giant beavers likely coexisted with humans in what is now North America to where they were native, since they did not disappear from the fossil record until about 11,000 years ago. Castoroides was the largest known rodent to have ever existed but, while similar in appearance to modern beavers, had a smaller brain-to-body ratio and different teeth that likely made them less able to build beaver dams.

3. Megatherium

Megatherium actually means ‘giant beast’, which is quite a suitable name given that they were among the largest mammals ever to roam the Earth. These
elephant-sized creatures were the ancestors of modern ground sloths. They lived until as recently as 10,000 years ago when climate change following the end of the last ice age likely played a central role in their extinction. Megatherium were almost certainly herbivorous like modern sloths, and they were closely related to the eremotherium, a contemporary giant sloth.

4. Deinosuchus

Living between 80 and 73 million years ago, deinosuchus was a contemporary of the later dinosaurs. A member of the highly successful crocodilian order, which survived the extinction of the dinosaurs, deinosuchus was very similar in appearance to its closest modern relative, the American alligator. However, with a body length of 35 feet, deinosuchus was even more terrifying than its ferocious modern relative. Deinosuchus, aptly meaning ‘terrible crocodile’ had one of the strongest bite forces of any animal, and likely preyed even on larger dinosaurs.

5. Carbonemys

An ancestor of modem turtles, carbonemys was the largest turtle to ever exist. It lived approximately 60 million years ago during the early Palaeocene epoch in what is now South America. Carbonemys evolved around five million years after the extinction of the dinosaurs The species was discovered relatively recently in 2005 when an enormous shell measuring 5”8’ was found in a coal mine in Columbia. That specimen remains the only one ever found to date, indicating that carbonemys lived in a rather small geographic and temporal range.

6. Titanoboa

A contemporary of the carbonemys, the titanoboa was the largest snake ever known to have existed. This terrifying creature was longer and heavier than any other snake, and it lived for around 10 million years after the extinction of the dinosaurs A member of the boidae family of non-venomous snakes, the titanoboa likely fed almost exclusively on fish, thriving in the lush tropical climate of what is now South America. More than 28 fossils of the 40-foot-long snake have been discovered, giving palaeontologists extensive insights into the climate and geography of the time.

7. Gigantopithecus

Primates have a long history dating back to the demise of the dinosaurs 66 million years ago, but early primates were usually tiny. However, gigantopithecus was undoubtedly an exception. The aptly named ‘giant ape’ lived in what is now southeast Asia, and it grew to a height of up to 10 feet and weighed over 1,000 pounds. The species exhibited enormous sexual dimorphism, with females being around half the size. Gigantopithecus lived from around nine-million years to 100,000 years ago.

8. Megalodon

Megalodon was a prehistoric shark that made even notorious apex predators like the modern great white shark look like small fish. Megalodon dominated the oceans between 20 and 2.6 million years ago, and it reached lengths of 60 feet, making it almost three times larger than the biggest among today’s sharks. Though vastly bigger, the megalodon closely resembled today’s great white shark in terms of appearance, but it would have preyed on even larger animals. After all, it’s teeth are significantly larger than human hands.

9. Meganeura

It wasn’t only the ancestors of reptiles, mammals and fish that grew to enormous sizes Meganeura was the largest insect ever known to exist. With a wingspan of 25 inches, this ancient predecessor to the dragonfly had a body the size of a domestic cat and lived 300 million years ago during the Carboniferous period. Meganeura, among other large insects at the time, has baffled the science world ever since its discovery in 1880 due to the fact that insects have an upper size limit. However, the size of the meganeura is now attributed to much higher oxygen levels at the time.

10. Phorusrhacid

More commonly known as terror birds, phorusrhacids were a group of extremely large and fast flightless birds. Their sharp claws and the fact that they could run down prey at speeds of at least 30 miles per hour have earned them their ominous nickname. Adult birds were almost 10 feet high, and they lived throughout the Palaeocene and Pleistocene eras until around 1.8 million years ago. Terror birds were ferocious apex predators with sharp beaks and claws that allowed them to literally rip their prey apart.

Final Words

Big enormous does come with its grave disadvantages, as evidenced in every major extinction events that the world has ever seen. After all, larger animals have much greater food and water requirements, making them particularly susceptible to climate change. For this reason, all non-avian dinosaurs, as well as numerous other species, were eradicated during the mass extinctions 66 million years ago, leaving only their hardier and, usually, smaller relatives to survive in the harsh new world.