Millions of years ago, giant animals were much more common than they are today.
Deinosuchus
With a length of nearly 11 meters and a weight of 2.5–5.5 tons, this ancient crocodile is often described as a reptilian monster. It was the largest predator inhabiting North America during the Cretaceous period, more than 75 million years ago.
According to Discovery magazine, research suggests that Deinosuchus hunted dinosaurs—an unsurprising fact given that it weighed twice as much as a Tyrannosaurus rex.
Scientists believe Deinosuchus had a lifespan of about 50 years, growing in size for the first 35 years. Despite being much larger than modern crocodiles, Deinosuchus closely resembled its present-day relatives in appearance.
Josephoartigasia monesi
The capybara is currently the world’s largest rodent, reaching a maximum weight of nearly 60 kg. However, more than 3 million years ago, the largest rodent to ever exist, Josephoartigasia monesi, had an average weight of up to 1.3 tons. This species once inhabited river estuaries and forested floodplains in what is now Uruguay.
Fossil remains suggest that Josephoartigasia monesi had large incisors with a bite force three times stronger than that of a tiger, likely used for self-defense or foraging. With relatively small molars, it was probably adapted to eating soft vegetation.
Megatherium americanum
During the Pliocene (5.3–2.6 million years ago) and Pleistocene (2.6 million–11,700 years ago) epochs, a giant sloth measuring 6 meters in length and weighing 4 tons roamed the land.
Found in the forests and grasslands of South America, Megatherium americanum was primarily herbivorous. However, it is believed that when the opportunity arose, this species was also capable of eating meat. Unlike modern sloths, which use their claws to climb trees, Megatherium americanum likely used its massive claws for digging burrows and tunnels.
Paraceratherium
More than 30 million years ago, an enormous hornless rhinoceros weighing approximately 30 tons—four times the weight of a modern elephant—roamed the Earth.
Although Paraceratherium measured nearly 8 meters in length and stood about 5.5 meters tall, it had a relatively small skull. Its long neck and legs allowed it to reach leaves and branches high above the ground.
Despite lacking the horns seen in modern rhinoceroses, Paraceratherium had a rather unusual set of teeth. It possessed two pairs of incisors—one on the lower jaw, slightly protruding forward, and another on the upper jaw, angled downward. This structure likely helped Paraceratherium grip tree branches firmly while feeding. To this day, it remains the largest land-dwelling mammal ever recorded.
Gigantopithecus
Gigantopithecus was the largest ape ever recorded. For more than 1.7 million years, this “beast” dominated the forests across East Asia, according to IFL Science.
Most scientists agree that Gigantopithecus went extinct at least 100,000 years ago, most likely due to environmental changes that affected its food supply. Estimates suggest that this giant primate stood about 3 meters tall and weighed between 200 and 300 kg.
Blue Whale
Unlike the other species mentioned above, the blue whale still exists today. It holds the title of the largest animal ever recorded, reaching lengths of nearly 31 meters and weighing up to 200 tons.
According to research published in 2021 by Matthew Savoca from Stanford University's Hopkins Marine Station, blue whales can consume 20 to 50 million calories per day. Witnessing a blue whale surfacing is always a breathtaking spectacle.
