It is the most complete mammal known from the Mesozoic of Gondwana.

They are the first mammals known to do so.

This would make them the longest lived mammal known.

This fish is not related to the marine mammals also known as dolphins (family Delphinidae).

The manatee, a large, fully aquatic marine mammal sometimes known as the sea cow.

He's an Olympian of a mammal known as a manatee, a male, about 10 feet long, 1,200 pounds, 30 to 50 years old.

It clearly belongs within a group of theriiform mammals known as the Spalacotherioidea.

The sea otter is one of the few nonprimate mammals known to use a tool while foraging.

He speculated that the 200 or so species of mammals then known might have descended from as few as 38 original forms.

These were hooved, predominantly carnivorous mammals known only from fossils.