The largest prehistoric mammal ever was the Indricotherium a prehistoric rhino like mammal the height of a modern giraffe and weighing 12 tons.
t.rex
The largest prehistoric animal ever was the Basilosaurus which was a 59 foot whale. The largest crocodilian was the 39 foot long Sarcosuchus Imperator.
Indricotherium
The largest mammal that ever lived is the blue whale. It is bluish gray, darker on the top than on the bottom.
The Indricotherium was the largest land mammal to ever live. It was about twenty five feet in length, 17 feet tall and weighed about 18000 kilograms.
The blue whale, alive today.
There are no land mammals in or on Antarctica. There are only marine mammals.
The Hippopotamus is the 3rd largest mammal.
The Blue Whale. Also known to be the largest animal ever.
By almost any absolute measurement, the blue whale is the biggest mammal living today. It can grow up to 100 feet and weigh more than 100 tons. On land its the African elephant.
Styxosaurus was not a mammal. It is a prehistoric marine reptile.
The blue whale is the largest mammal on earth.