Obama signing makes it national mammal.

• Position: Bison

On May 9, the National Bison Legacy Act was signed into law by Pres. Barack Obama, officially making the American bison the national mammal of the U.S. This majestic animal joins the ranks of the bald eagle as the official symbol of our country--and, much like the eagle, it is one of the greatest conservation success stories of all time, reports the Department of the Interior.

In prehistoric times, millions of bison roamed North America--from the forests of Alaska and the grasslands of Mexico to Nevada's Great Basin and the eastern Appalachian Mountains. By the late 1800s, however, there only were a few hundred left in the U.S. after settlers pushed west, reducing the animal's habitat and hunting it to near extinction. Had it not been for a few private individuals working with tribes, states, and the Interior Department, the bison would be extinct today.

Here are some interesting facts about the American bison:

* Bison are the largest mammal in North America. Male bison (called bulls) weigh up to 2,000 pounds and stand six feet tall, while females (called cows) weigh up to 1,000 pounds and reach a height of four to five feet. Calves weigh 30-70 pounds at birth.

* Since the late 19th century, the Department of the Interior has been the primary national conservation steward of bison. Public lands managed by Interior support 17 bison herds--or approximately 10,000 bison--in 12 states, including Alaska.

* While bison and buffalo are used interchangeably, in North America the scientific name is bison. Actually, it is Bison bison bison (genus: Bison, species: bison, subspecies: bison). Historians believe that the term "buffalo" grew from the French word for beef, boeuf.

* Yellowstone National Park is the only place in the U.S. where bison have lived continuously since prehistoric times. What makes Yellowstone's bison so special is that they are the pure descendants (free of cattle genes) of early bison that roamed our country's grasslands. As of July 2015, Yellowstone's bison population was estimated at 4,900 --making it the largest bison population on public lands.

* A "red dog" is a baby bison. Calves tend to be born from late March through May and are orange-red in color, earning them the nickname. After a few months, their hair starts to change to dark brown and their characteristic shoulder hump and horns begin to grow.

* Bison have been integral to Native American tribal societies, providing them with food, clothing, fuel, tools, shelter...