The natural world is full of wonders, and animals are chief among these wonders. Making their homes across every continent, they come in all shapes and sizes. They often boast uncanny abilities to match. These traits are enough to wow you with exotic splendor, but they’re just the tip of the iceberg.
Many animal species used to be far larger than they are today. Their prehistoric ancestors dwarfed modern specimens, creating a radically different hierarchy in nature. For whatever reason, evolution dictated that they must be smaller to survive the shifting climate. These changes may undermine their visual impact in many people’s eyes, especially when put into a broader perspective. On the other hand, it lets you appreciate just how unpredictable nature can be. Most importantly, though, it makes you glad these giants aren’t around anymore.
Related: 10 North American Animals with Misplaced Reputations
10 Sharks
Sharks are the most iconic aquatic predators in the world. That’s thanks in no small part to Jaws, but the animals are impressive enough without Hollywood embellishment. They constantly prowl the seas, gorging themselves on whatever prey they can find. Not counting the krill-eating whale shark, the biggest example is the great white shark. This specimen can reach lengths of 19 feet (5.8 meters). However, its ancestors could swallow it in one bite.
Enter the Otodus megalodon. Also known as the “megalodon,” this monster lived between 23 and 3 million years ago. It may look like an ordinary shark from a distance, but its sheer scale soon puts that thought to rest. Scientists estimate that it reached lengths of 67 feet (2.4 meters). With that size and the killer bite to match, the megalodon could take down equally large targets like whales. If it was still around today, even cruise liners or battleships might not be safe.[1]
9 Crocodiles
Nearly as infamous as sharks are crocodiles. These reptiles dominate rivers and lakes. Ambush predators by nature, they lie in wait for unsuspecting land animals to drink or cross the water. They then leap out and grab their victims in the blink of an eye, drowning and lacerating them with savage death rolls. Saltwater crocodiles are the largest examples, ranging between 12 and 18 feet (3.7 and 5.5 meters) in length. Of course, that’s nothing next to what came before.
Deinosuchus puts modern crocodilians to shame. This Cretaceous predator existed between 82 and 73 million years ago. Not only did it live alongside the dinosaurs, but the massive land reptiles were part of its diet. Deinosuchus reached lengths of 35 feet (10.7 meters), making it more than a match for its terrestrial rivals. It’s further proof that the true prehistoric giants dwelled in the water.[2]
8 Elephants
Elephants are already the largest land animals. Though not as tall as giraffes, they compensate through sheer mass and power. The African variety can grow over 12 feet (3.7 meters) in height and 30 feet (9.1 meters) in length. Combining that huge size with unmatched muscle, they can topple an entire tree to reach its delectable leaves. When you think of prehistoric elephants, you might picture woolly mammoths. These hairy beasts weren’t the only examples, however.
The various types of Palaeoloxodon more closely resembled today’s elephants in both their warm surroundings and leathery appearance. They also subsisted on plants, often leaving trampled trunks in their wake. The difference lies in their proportions. While their length was the same (give or take), Palaeoloxodon bulls could reach 13 feet (4 meters) tall. That minor deviation could be attributed to their place in history, as they only existed 2 million to 11,000 years ago. That’s barely time for any evolutionary change.[3]
7 Bears
Bears are also at the top of the food chain. Standing between 6 and 9 feet (1.8 and 2.7 meters) tall (on their hind legs) and weighing 600 to 1200 pounds (272 to 544 kg), they’re the largest predators currently on land. That’s not to say they’re strictly carnivorous; they happily eat any edible items they can find. They usually binge to build up fat levels before winter. After all, they need ample reserves to survive hibernation. That need was even greater during the Ice Age.
This period was home to cave bears. These mammals lived about 1 million to 24,000 years ago. Their average height was around 9 feet (2.7 meters) when standing upright, which is comparable to the largest bears found today. However, they’re far bigger when factoring in their weight—ranging from 800 to 2,000 pounds (363 to 9.7 kg). Suffice it to say that they needed to eat a lot more to get through the cold.[4]
6 Millipedes
Creepy crawlies may be small, but they still inspire fear in plenty of people. Millipedes are chief among them. These little guys are only a few centimeters in length, with the largest reaching only 15 inches (38 cm). Despite that minuscule size, they have numerous legs on each body segment. They use these appendages to inch their way through woodland areas, devouring all manner of plants and fungi. Those factors make them virtually harmless to animals and easy pickings for predators. You can’t say the same for their ancestors, though.
Arthropleura was a massive millipede of yesteryear. It grew between 6 and 7 feet (1.8 and 2.1 meters) long. That size meant that it had virtually no natural predators. Moreover, it put most plants on the menu. Arthropleura was not only herbivorous but possibly omnivorous. Either way, it was spoiled for choice since it lived in a densely wooded period called the Carboniferous, specifically between 345 and 290 million years ago. Of course, it wasn’t the only example from that time.[5]
5 Dragonflies
The Carboniferous was basically the period of big bugs. Another testament to that fact was the dragonflies that roamed the skies. Today, these flying insects frequent water bodies in search of food. They use their aerodynamic skills to ambush other bugs. Although exact size varies with each species, most specimens are around 3 inches (7.6 cm) long and sport wingspans between 2 and 5 inches (5 and 12.7 cm). Those stats put them on the larger side when it comes to insects, but their prehistoric counterparts put them to shame.
Meganeura could reach lengths of 13 inches (33 cm). Its wingspan was even more surprising, clocking in at over 2 feet (60 cm). Although it existed 350 to 280 million years ago, the dragonfly’s diet was much the same as it is today. Considering the size of the insects during the Carboniferous, that’s no small feat. It gave Meganeura a reputation akin to an actual dragon.[6]
4 Sloths
Sloths are unassuming animals. They slowly climb trees and feast on leaves. Their claws might look intimidating at first, but the animal’s unimpressive size—about 2 feet (0.6 meters)—offsets any sense of danger. Those mundane qualities may be why these shaggy guys barely ever touch the ground. Better to avoid predators that way. That said, their extinct brethren were the polar opposite.
Ground sloths were a sight to behold. These colossal creatures were 10 feet (3 meters) long and over 2,000 pounds (9.7 kg). Although they still subsisted on plants, they didn’t have to climb trees for safety. Their imposing size complemented their long claws, making them a tough target for all but the most elite predators. It’s a good thing they lived over 13,000 years ago.[7]
3 Rhinos
Elephants aren’t the only tusked animals ruling the plains. The rhinoceros is nearly as formidable with its sharp horns. If threatened, it doesn’t hesitate to use this weapon in a powerful charge. Such an attack can be fatal considering the animal’s 12-foot (3.7-meter) length and 3,000–7,000-pound (1,360–3,175-kg) weight. Predators generally leave rhinos to eat their plants in peace. Like elephants, though, these leathery herbivores have a hairy counterpart.
Woolly rhinos were exactly what they sound like. They resembled their modern cousins in structure, albeit with a thick layer of hair. This coat protected them from the cold climate between 5 million and 11,000 years ago. The other notable difference was their size. Stretching over 12 feet (3.7 meters) long and weighing 6,400 pounds (2,903 kg), they outclassed today’s rhinos by a narrow margin, mainly due to their greater heights. That said, their diets remained herbivorous. That seems to be the pattern for the most awesome animals.[8]
2 Birds
Many scientists obviously believe that birds descend from dinosaurs. Although they’re significantly smaller (from a few inches to a few feet), they boast similar proportions and carnivorous tendencies. These aerial theropods snatch their prey with their razor-sharp beaks and killer talons. Despite those mirrored qualities, they have a closer ancestor, which was elite in its own right.
The aptly named “terror birds” existed from 9 to 4 million years ago. They were the top predators of their turf, standing up to 10 feet (3 meters) tall. Although flight was impossible due to tiny wings, their immense beaks and muscular legs were enough to catch and kill most terrestrial prey. These deadly perks help bridge the gap between dinosaurs and today’s birds.[9]
1 Snakes
Snakes are among the most varied reptiles in the world. Their sizes range from a few inches to over 20 feet (6.1 meters), and they eat whatever animals will fit in their mouths. Small specimens may get by on rats and insects, while larger examples might tackle deer, sheep, or capybaras. Prehistoric serpents achieve even greater feats.
The most sizeable snake ever discovered was the Titanoboa cerrejonensis. Measuring 42 feet (12.8 meters) long, it was over twice the size of the biggest modern snakes. That scale enabled it to constrict and consume most animals. Given that it lived between 66 million and 56 million years ago, its diet likely consisted of the colossal crocodiles, fish, and turtles of that era. It even ate other snakes. Slithering descendants are lucky it’s extinct.[10]