They are among only a handful of new large land mammals discovered worldwide this century.
For land mammals, fur or hair is the primary heat insulation.
Some grew larger than any land mammal ever has, but very little of that increase went into the brain.
And while we're talking of land mammals adapted to seeking food by sea, we should mention man, too.
To learn about some of Alaska's most popular land mammals and where you might see them, click on the links below.
The park is also home to some fantastic marine and land mammals.
About 23 million years ago another group of bearlike land mammals started returning to the sea.
Until now, the oldest traces of land mammals there were only 100,000 years old.
This is reflected in the absence of land mammals other than bats.
This was the first evidence of land mammals having lived in Antarctica.