A titanosaur is a large, herbivorous dinosaur that lived during the Cretaceous period. The first titanosaurs were discovered in the 1850s, and since then, many more have been found. Titanosaurs are the largest known land animals that have ever lived; they were up to 30 meters (100 feet) long and weighed up to 70 metric tons (150,000 pounds).
Titanosaurs belonged to a group of dinosaurs called sauropods, which also included such well-known creatures as brontosaurus and diplodocus. Sauropods were characterized by their long necks, tails, and small heads; they walked on all fours with their weight evenly distributed between their four legs. Titanosaurs had very thick bones, which made them much heavier than other types of dinosaurs.
Most titanosaurs lived in warm climates near the equator. They probably fed on low-lying plants such as ferns and shrubs. It is not known for sure how titanosaurs reproduced, but it is likely that they laid eggs like other dinosaurs.
Although they were once thought to be sluggish animals because of their size, recent studies have shown that titanosaurs could move fairly quickly when necessary. For example, one study found that a titanosaur could walk at a speed of 5 kilometers per hour (3 miles per hour).
Titanosaurs went extinct at the end of the Cretaceous period along with all other dinosaurs. The exact reason for this mass extinction is still unknown, but scientists believe that a comet or asteroid hitting Earth might have caused it.