The Antarctic blue whale (Balaenoptera musculus ssp. Intermedia) is the biggest animal on the planet, weighing up to 400,000 pounds (approximately 33 elephants) and reaching up to 98 feet in length. The whale has a heart the size of a small car, and during the main feeding season, it consumes around 7936 pounds of krill per day. It is the loudest animal on Earth, even louder than a jet engine -- its calls reach 188 decibels while a jet reaches 140 decibels. The whales' low-frequency whistle can be heard for hundreds of miles and is probably used to attract other blue whales.
Megalodon (Otodus megalodon),meaning "big tooth", is an extinct species of mackerel shark that lived approximately 23 to 3.6 million years ago (Mya), from the Early Miocene to the Pliocene epochs. It was formerly thought to be a member of the family Lamnidae and a close relative of the great white shark (Carcharodon carcharias). However, it is now classified into the extinct family Otodontidae, which diverged from the great white shark during the Early Cretaceous.The most recent estimate with the least error range suggests a maximum length estimate up to 20 meters (66 ft), although the modal lengths are estimated at 10.5 meters (34 ft). Extrapolation from a vertebral centra with dimensions based on the great white shark suggests that a megalodon about 16 meters (52 ft) long weighs up to 48 metric tons (53 short tons), 17 meters (56 ft) long weighs up to 59 metric tons (65 short tons), and 20.3 meters (67 ft) long (the maximum length) weighs up to 103 metric tons (114 short tons).
Although paleontologists claim to have identified bigger dinosaurs, Argentinosaurus is the largest whose size has been backed up by convincing evidence. This gigantic titanosaur (named after Argentina, where its remains were discovered in 1986) measured about 120 feet from head to tail and may have weighed nearly 100 tons.Just one of the vertebra of Argentinosaurus is over four feet thick. Other, less-well-attested contenders for the "biggest dinosaur" title include Futalognkosaurus, Bruhathkayosaurus and Amphicoelias; a new contender, still unnamed and about 130 feet long, was recently discovered in Argentina.
Ichthyosaurs, the "fish lizards," were large, dolphin-like marine reptiles that dominated the seas of the Triassic and Jurassic periods. For decades, the biggest ichthyosaur was believed to be Shonisaurus, until the discovery of a super-sized (75 ton) Shonisaurus specimen prompted the erection of a new genus, Shastasaurus (after California's Mount Shasta). As huge as it was, Shastasaurus subsisted not on comparably sized fish and marine reptiles, but on soft-bodied cephalopods and other wee marine creatures (making it broadly similar to the plankton-filtering Blue Whales populating the world's oceans today).
Whales haven't always been ocean-dwellers—their ancestors lived on land, and they moved to the water about 50 million years ago. They had some awkward in-between years before becoming the whales we know and love today (and by awkward, we mean horrifying). Take Basilosaurus, whose three-foot skull you can see in our Evolving Planet exhibition. Recent studies have suggested that this 60-foot leviathan had a bite force to rival that of T. rex, which it put to good use cracking open the skulls of other, smaller whales (you can see Basilosaurus tooth marks on their skulls).Measuring 15–20 m (49–66 ft), Basilosaurus is one of the largest animals known to exist between the K–Pg extinction event 66 million years ago (mya) and around 15 million years ago when modern cetaceans began to reach enormous sizes and weigh approx 60 Tons.
Shark-like Helicoprion is a long-lived genus of extinct Eugeneodontid holocephalid fish. It lived 250 million years ago. Their jaw was composed of a coil of teeth which acted as a saw. The Helicoprion attracted media attention in 2013 as a new study that explained the mystery of their saw-like jaws was published. However, the physical identity of it remained hidden in 250 million years old rocks.The most recent estimate with the least error range suggests a maximum length estimate up to 15 meters(47 meters), weighs up to 28 metric tons.
Steller's sea cow (Hydrodamalis gigas) is an extinct sirenian described by Georg Wilhelm Steller in 1741. At that time, it was found only around the Commander Islands in the Bering Sea between Alaska and Russia; its range extended across the North Pacific during the Pleistocene epoch, and likely contracted to such an extreme degree due to the glacial cycle. It is possible indigenous populations interacted with the animal before Europeans. Steller first encountered it on Vitus Bering's Great Northern Expedition when the crew became shipwrecked on Bering Island. Much of what is known about its behavior comes from Steller's observations on the island, documented in his posthumous publication On the Beasts of the Sea. Within 27 years of its discovery by Europeans, the slow-moving and easily-caught mammal was hunted into extinction for its meat, fat, and hide.Steller's sea cows are reported to have grown to 8 to 9 m (26 to 30 ft) long as adults, much larger than extant sirenians.[6] In 1987, a rather complete skeleton was found on Bering Island measuring 3 m (9.8 ft).[7][8] In 2017, another such skeleton was found on Bering Island measuring 5.2 m (17 ft), and in life probably about 6 m (20 ft).[9] Georg Steller's writings contain two contradictory estimates of weight: 4 and 24.3 Tons.
Ever since its scattered, oversized remains were discovered in the early 20th century, Indricotherium has occasioned controversy among paleontologists, who have named this giant mammal not once, but three times--Indricotherium, Paraceratherium and Baluchitherium have all been in common usage, with the first two currently battling it out for supremacy. (For the record, Paraceratherium seems to have won the race among paleontologists, but Indricotherium is still preferred by the general public--and may yet wind up being assigned to a separate, but similar, genus.) Whatever you choose to call it, Indricotherium was, hands-down, the largest terrestrial mammal that ever lived, approaching the size of the giant sauropod dinosaurs that preceded it by over a hundred million years. An ancestor of the modern rhinoceros, the 15-to-20-ton Indricotherium had a relatively long neck (though nothing approaching what you'd see on a Diplodocus or Brachiosaurus) and surprisingly thin legs with three-toed feet, which years ago used to be portrayed as elephant-like stumps. The fossil evidence is lacking, but this huge herbivore probably possessed a prehensile upper lip--not quite a trunk, but an appendage flexible enough to allow it to grab and tear the tall leaves of trees.
Mosasaurus ("lizard of the Meuse River") is the type genus (defining example) of the mosasaurs, an extinct group of aquatic squamate reptiles. It lived from about 82 to 66 million years ago during the Campanian and Maastrichtian stages of the Late Cretaceous. The earliest fossils of Mosasaurus known to science were found as skulls in a chalk quarry near the Dutch city of Maastricht in the late 18th century, which were initially thought to have been the bones of crocodiles or whales. Traditional interpretations have estimated the maximum length of the largest species, M. hoffmannii, to be up to 17.1 meters (56 ft), making it one of the largest mosasaurs, although some scientists consider this an overestimation with recent estimates suggesting a length closer to 13 meters (43 ft).
Better known as the "SuperCroc," the 40-foot-long Sarcosuchus weighed as much as 15 tons--at least twice as long, and ten times as heavy, as the biggest crocodiles alive today. Despite its enormous size, though, Sarcosuchus appears to have led a typical crocodilian lifestyle, lurking in the African rivers of the middle Cretaceous period and launching itself at any dinosaurs unlucky enough to draw too near. It's possible that Sarcosuchus tangled occasionally with another river-dwelling member of this list, Spinosaurus.
The steppe mammoth (Mammuthus trogontherii, sometimes Mammuthus armeniacus) is an extinct species of Elephantidae that ranged over most of northern Eurasia during the late Early and Middle Pleistocene, approximately 1.8 million-200,000 years ago. It evolved in Siberia during the Early Pleistocene from Mammuthus meridionalis. It was the first stage in the evolution of the steppe and tundra elephants and the ancestor of the woolly mammoth and Columbian mammoth of the later Pleistocene. Populations of steppe mammoth may have persisted in northern China and Mongolia as late as 33,000 years ago.
You probably thought the winner in this category would be Tyrannosaurus Rex, but it's now believed that Spinosaurus (which had a huge, crocodile-like snout and a sail of skin sprouting from its back) was slightly heavier, weighing as much as 10 tons. And not only was Spinosaurus big, but it was agile as well: recent evidence points to it being the world's first identified swimming dinosaur. (By the way, some experts insist that the biggest meat-eater was the South American Giganotosaurus, which may have matched, and occasionally even outclassed, its northern African cousin.)
Poor Tyrannosaurus Rex: once considered (and often assumed) to be the world's biggest carnivorous dinosaur, it has since been surpassed in the rankings by Spinosaurus (from Africa) and Giganotosaurus (from South America). Thankfully, though, North America can still lay claim to the world's biggest tyrannosaur, a category that also includes not-quite-T.-Rex sized predators like Tarbosaurus and Albertosaurus. (By the way, there's evidence that T. Rex females outweighed males by a half ton or so -- a classic example of sexual selection in the theropod kingdom.)
Not for nothing was Kronosaurus named after the mythical Greek god Cronos, who ate his own children. This fearsome pliosaur--a family of marine reptiles characterized by their squat torsos, thick heads perched on short necks, and long, ungainly flippers--ruled the seas of the middle Cretaceous period, eating pretty much anything (fish, sharks, other marine reptiles) that happened across its path. It was once believed that another famous pliosaur, Liopleurodon, outclassed Kronosaurus, but it now appears that this marine reptile was roughly the same size, and perhaps a bit smaller.
Elasmotherium also know as Elasmotherium sibiricum is an extinct genus of large rhinoceros endemic to Eurasia during Late Miocene through the Pleistocene, existing at least as late as 39,000 years ago in the Late Pleistocene.[2] A more recent date of 26,000 BP is considered less reliable.[2] It was the last surviving member of Elasmotheriinae, a distinctive group of rhinoceroses separate from the group that contains living rhinoceros (Rhinocerotinae). The two groups are estimated to have split at least 35 million years ago according to fossils and molecular evidence.The known specimens of E. sibiricum reach up to 4.5 m (15 ft) in length, with shoulder heights up to 2.5 m (8 ft 2 in), while E. caucasicum reaches at least 5 m (16 ft) in body length with an estimated mass of 3.5–5 tonnes (3.9–5.5 short tons).
Along with Glyptodon, Megatherium, aka the Giant Sloth, was one of the innumerable megafauna mammals of Pleistocene South America. (Cut off from the mainstream of evolution during much of the Cenozoic Era, South America was blessed with copious vegetation, allowing its mammal population to grow to truly enormous sizes.) Its long claws are a clue that Megatherium spent most of its day ripping the leaves off trees, but this three-ton sloth may not have been averse to feasting on the occasional rodent or snake.
Elasmosaurus is a genus of plesiosaur that lived in North America during the Campanian stage of the Late Cretaceous period, about 80.5 million years ago. Measuring 10.3 meters (34 ft) in length and 2 to 3 tons in body mass, Elasmosaurus would have had a streamlined body with paddle-like limbs, a short tail, a small head, and an extremely long neck. The neck alone was around 7.1 meters (23 ft) long. Along with its relative Albertonectes, it was one of the longest-necked animals to have lived, with the second largest number of neck vertebrae known, 72, 4 less than Albertonectes.
Three million years ago, toward the end of the Pliocene epoch, the Central American isthmus rose up from the murky depths to create a land bridge between North and South America. At that point, a population of Arctodus (aka the Giant Short-Faced Bear) made the trip south, eventually going on to spawn the truly imposing, two-ton Arctotherium. The only thing keeping Arctotherium from supplanting Andrewsarchus as the biggest terrestrial mammalian predator was its presumed diet of fruits and nuts.
Perhaps because its name is so similar to Australopithecus, many people mistake Gigantopithecus for a hominid, the branch of Pleistocene primates directly ancestral to human beings. In fact, though, this was the largest ape of all time, about twice the size of a modern gorilla and presumably much more aggressive. (Some cryptozoologists believe that the creatures we variously call Bigfoot, Sasquatch and Yeti are still-extant Gigantopithecus adults, a theory for which they have adduced not a shred of credible evidence.)
Archelon is an extinct marine turtle from the Late Cretaceous, and is the largest turtle ever to have been documented, with the biggest specimen measuring 5 m (16 ft) from head to tail and 2,200 kg (4,900 lb) in body mass. It is known only from the Dakota Pierre Shale and has one species, A. ischyros. In the past, the genus also contained A. marshii and A. copei, though these have been reassigned to Protostega and Microstega, respectively. The genus was named in 1895 by American paleontologist George Reber Wieland based on a skeleton from South Dakota, who placed it into the extinct family Protostegidae. The leatherback sea turtle (Dermochelys coriacea) was once thought to be its closest living relative, but now, Protostegidae is thought to be a completely separate lineage from any living sea turtle.
Titanoboa is an extinct genus of very large snakes that lived in what is now La Guajira in northeastern Colombia. They could grow up to 12.8 m (42 ft), perhaps even 14.3 m (47 ft) long and reach a weight of 1,135 kg (2,500 lb). This snake lived during the Middle to Late Paleocene epoch, around 60 to 58 million years ago following the extinction of the dinosaurs. Although originally thought to be an apex predator, the discovery of skull bones revealed that it was more than likely specialized in preying on fish. The only known species is Titanoboa cerrejonensis, the largest snake ever discovered, which supplanted the previous record holder, Gigantophis garstini.
Reconstructed on the basis of a single, enormous skul—discovered by the famous fossil-hunter Roy Chapman Andrews during an expedition to the Gobi Desert—Andrewsarchus was a 13-foot-long, one-ton meat eater that may well have feasted on megafauna mammals like Brontotherium (the "thunder beast"). Given its enormous jaws, Andrewsarchus may also have supplemented its diet by biting through the hard shells of equally gigantic prehistoric turtles!