Science, Tech, Math › Animals & Nature Mapusaurus Share Flipboard Email Print Mapusaurus. Wikimedia Commons Animals & Nature Dinosaurs Carnivores Basics Paleontologists Dinosaurs & Birds Herbivores Marine Reptiles Prehistoric Mammals Amphibians Birds Habitat Profiles Mammals Reptiles Wildlife Conservation Insects Marine Life Forestry Evolution View More By Bob Strauss Science Writer B.S., Cornell University Bob Strauss is a science writer and the author of several books, including "The Big Book of What, How and Why" and "A Field Guide to the Dinosaurs of North America." our editorial process Bob Strauss Updated March 06, 2017 Name: Mapusaurus (indigenous/Greek for "earth lizard"); pronounced MAP-oo-SORE-us Habitat: Woodlands of South America Historical Period: Middle Cretaceous (100 million years ago) Size and Weight: About 40 feet long and three tons Diet: Meat Distinguishing Characteristics: Large size; serrated teeth; powerful legs and tail About Mapusaurus Mapusaurus was discovered all at once, and in a big heap--an excavation in South America in 1995 that yielded hundreds of jumbled bones, which required years of work by paleontologists to sort out and analyze. It wasn't until 2006 that the official "diagnosis" of Mapusaurus was released to the press: this middle Cretaceous menace was a 40-foot-long, three-ton theropod (i.e., meat-eating dinosaur) closely related to the even bigger Giganotosaurus. (Technically, both Mapusaurus and Giganotosaurus are classified as "carcharodontosaurid" theropods, meaning they're both also related to Carcharodontosaurus, the "great white shark lizard" of middle Cretaceous Africa.) Interestingly, the fact that so many Mapusaurus bones were discovered jumbled together (amounting to seven individuals of different ages) can be taken as evidence of herd, or pack, behavior--that is, this meat-eater may have hunted cooperatively in order to take down the huge titanosaurs that shared its South American habitat (or at least the juveniles of these titanosaurs, since a fully grown, 100-ton Argentinosaurus would have been virtually immune from predation). On the other hand, a flash flood or other natural disaster could also have resulted in a significant accumulation of unrelated Mapusaurus individuals, so this pack-hunting hypothesis should be taken with a big grain of prehistoric salt!