Dinosaurs
A group of dinosaurs called sauropods, which flourished between the late Triassic and Cretaceous periods, are considered the largest land animals ever to walk the Earth. New fossil evidence and the discovery of previously unknown species has changed which is considered the champion among them, but one likely contender for all-time heaviest is Argentinosaurus, named for the country in which the remains of its massive vertebrae were unearthed. This huge member of the aptly named titanosaur family may have weighed 100 tons and spanned 90 feet in length.
Indricotherium
Indricotherium, a huge relative of modern rhinoceroses, also called Paraceratherium, was the biggest land mammal ever. Known from Asian sediments 16.6 to 30 million years old, Indricotherium may have weighed 30 tons, several times the weight of today's African bush elephant. Standing 18 feet at the shoulder, this herbivore was a titanic browser, munching on high canopy foliage.
Elephants
In the modern world, the largest land animals are the several species of elephant native to Africa and Asia. Biggest of all is the African bush or savanna elephant, which inhabits a patchy range of sub-Saharan Africa, favoring open woodland, scrub and even desert environments. Large bull bush elephants tip the scales at 14,000 lbs. and span 25 feet from trunk to tail. The largest known specimen is a 22,000-lb. bull, 13 feet at the shoulder, on display at the Smithsonian's National Museum of Natural History in Washington, D.C. Somewhat smaller but still heavier than any other living land animals are the African forest elephant, an inhabitant of the continent's equatorial forests, and the Asian elephant of India, Thailand and other parts of southern and southeastern Asia.
Giraffe
If African bush elephants are the heavyweight champions of the land-animal world, their frequent neighbor, the giraffe, takes top prize in the height department. These gangly, exotic-looking ungulates browse acacias and other trees in savannas and woodlands across a reduced range of sub-Saharan Africa. The biggest bulls may stand over 18 feet tall and weigh more than 4,000 lbs.
Other Contenders
A number of other huge ungulates, mostly African in origin, round out the top ranks of biggest land animals. Two of the heaviest land animals after the elephants are the white rhinoceros and hippopotamus, both of sub-Saharan Africa. These prehistoric-looking hoofed mammals have similar average weights, but exceptional hippos may weigh 8,000 lbs., compared with around 6,000 lbs. for a big white rhino bull. Other titanic animals include the greater one-horned rhinoceros and gaur of Asia and Africa's black rhino.