Largest herbivorous dinosaur
At the moment, the largest known dinosaur seems to be Argentinosaurus, a long-necked sauropod that lived 94 million years ago in Argentina. This massive creature is estimated to have stretched 100 feet long and weighed more than 73 tons. Other contenders in the roughly 100-foot range are Supersaurus, Sauroposeidon and Futalognkosaurus.
But one dinosaur may have been much, much bigger. In 1878, paleontologist Edward Drinker Cope gave the name Amphiocoelias fragillimus to a dinosaur represented by a five-foot-high neural arch, the top bit of a single vertebra. This must have belonged to an enormous dinosaur, but no other bones were ever found and this single specimen mysteriously disappeared more than a century ago. Paleontologist Kenneth Carpenter estimated that Amphiocoelias may have been anywhere from 130 to 200 feet long and weighed over 100 tons. Was this Jurassic giant truly the biggest dinosaur—and biggest animal—of all time? Until someone finds better fossils, we may never know.