This is Scientific Americans 60 Second Science.

I'm Steve Mursky.

Today, November 4th is National Bison Day, celebrating the animal that last year Congress and the president designated as the

official national mammal of the United States. For good reason, the American

bison, also called the buffalo, is the iconic animal that helped mold the ecology of the Great Plains

and played a central role in the cultural life of multiple tribes of Native Americans,

including the Arapahoe and Lakota.

Today's healthy bison herds owe a lot to time their ancestors spent in, of all places,

the Bronx in New York City.

Well, historically, the Bronx you played York City. Well, historically the Bronx

you played a very important role in saving Bison.

Patrick Thomas, Vice President of the Wildlife Conservation Society

and Associate Director of its Bronx Zoo.

In the early 1900s, when Bison numbers were at their lowest in the species was facing extinction,

the Bronx Zoo acquired as many bison as they could, bred them, and then sent offspring from that breeding herd out west to

re-establish herds in the wild.

Thomas is involved in efforts with the zoo's current herd of bison.

Right now we're working to establish a herd of genetically pure bison at the zoo.

Today there are about 500,000 bison in the US,

but there's only about between 5 and 6,000 that are genetically pure bison.

The rest have some small trace amounts of domestic cow genes in them.

So we're establishing a herd of pure bison breeding them and again our goal is to take offspring from those pure bison and establish pure bison herds out west.

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