Identifying the largest dinosaurs ever lived isn’t an easy task, because it’s very rare to unearth a complete fossil. Furthermore, only a tiny percentage of these amazing animals ever fossilized, and most of these “lucky” bodies will remain buried underground forever. So, we may never know exactly what dinosaur was the biggest (or the tiniest) ever.
Despite this fact, size always has been one of the most interesting aspects of these prehistoric animals. There are extreme variations in their size, from the tiny hummingbirds, which can weigh as little as three grams, to the titanosaurs, which could weigh as much as 70 tonnes, or even more.
Here are some of the largest dinosaurs ever lived.
Biggest Dinosaur Ever: Patagotitan mayorum
Biggest Herbivorous Dinosaur: Argentinosaurus huinculensis
Previously, Argentinosaurus huinculensis (meaning “Argentine lizard”) was thought to be the largest, longest and heaviest dinosaur ever lived. It is is a genus of titanosaur sauropod dinosaur first discovered in Argentina (hence it is named Argentinosaurus). It lived on the then-island continent of South America somewhere between 94 and 97 million years ago, during the Late Cretaceous Epoch.
Its size was first estimated like: up to 39.7 meters (130 ft) in length, 7.3 meters (24 ft) in height, 80–100 tonnes (88–110 short tons) in weight. More recently, the weight estimate has been revised to 73 tons. Its maximum length also revised to 35 meters (115 feet). Scott Hartman, who known for his skeletal reconstructions (he has supplied skeletal and life reconstructions for numerous books and museums) suggests that since Argentinosaurus would have a shorter tail and narrower chest than Puertasaurus (another titanosaurian sauropod), suggesting that it was slightly smaller than other giant titanosaurs.
Studies show that an Argentinosaurus do not stop growing their entire lives. One article found that Argentinosaurus hatchlings would have had to grow 25,000 times their original size before reaching adult size.
Biggest Carnivorous Dinosaur: Spinosaurus aegyptiacus
This terrifying giant was the largest, longest and heaviest carnivorous ever lived. Spinosaurus (meaning “spine lizard”) is a genus of theropod dinosaur that lived in what now is North Africa, during the lower Albian to lower Cenomanian stages of the Cretaceous period, about 112 to 97 million years ago.
Since its discovery, Spinosaurus has been a contender for the longest and largest theropod dinosaur. Its size is estimated up to 16 to 18 meters (52 to 59 ft) in length and 11.7 to 16.7 tonnes (12.9 to 18.4 short tons) in weight.
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.
What about T. Rex?
Tyrannosaurus Rex once widely considered (and often assumed) to be the world’s biggest carnivorous dinosaur, but not any more. It is still among the largest known land predators and may have exerted one of the largest biting forces among all animals: a 2012 study by scientists Karl Bates and Peter Falkingham suggested that the bite force of Tyrannosaurus could have been the strongest of any terrestrial animal that has ever lived. The calculations suggested that adult T. rex could have generated from 35,000 to 57,000 Newtons of force in the back teeth. Even higher estimates were made by professor Mason B. Meers of the University of Tampa in 2003. In his study, Meers estimated a possible bite force of around 183,000 to 235,000 Newtons or 18.3 to 23.5 metric tons (20.2 to 25.9 short tons).
But in size, it has been surpassed in the rankings by Spinosaurus and Giganotosaurus. The largest complete specimen, located at the Field Museum of Natural History under the name FMNH PR2081 and nicknamed Sue, measured 12.3 meters (40 ft) long, and was 4 meters (13 ft) tall at the hips. Mass estimates have varied widely over the years, from more than 7.2 metric tons (7.9 short tons), to less than 4.5 metric tons (5.0 short tons), with most modern estimates ranging between 5.4 metric tons (6.0 short tons) and 6.8 metric tons (7.5 short tons).