This is Scientific American — 60-Second Science. I'mSteve Mirsky.
Today, November 4, is National Bison Day—celebrating the animal that last year Congress andthe President designated as the official NationalMammal of the United States. For good reason: theAmerican bison, also called the buffalo, is the iconicanimal that helped mold the ecology of the Great Plains and played a central role in thecultural life of multiple tribes of Native Americans, including the Arapaho 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 Zoo played a very important role in saving bison."
Patrick Thomas, Vice President of the Wildlife Conservation Society and Associate Director of itsBronx Zoo.
"In the early 1900s when bison numbers were at their lowest and the species was facingextinction, 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 thereare about 500,000 bison in the U.S., but there's only about between 5- and 6,000 that are genetically pure bison. The rest have 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."
In what would be a continuation of one of the earliest success stories in Americanconservation.
Ffor Scientific American — 60-Second Science. I'm Steve Mirsky.
1. designate as 标示；把…定名为；称呼；
例句：We're going to designate this room as a no-smoking area.
2. be involved in 卷入的；参与的；与…有密切关联的；
例句：So I'm involved in a different kind of campaign, to try to change enough minds tomake it a new reality.
3. a herd of 兽群；畜群；
例句：A herd of elephants lolloped across the plains towards a watering hole.