Our National Mammal - NYTimes.com The United States has a national bird, of course - the bald eagle, which was adopted as such on June 20, 1782. Last week, Senator Mike Enzi, a Republican of Wyoming, and Senator Tim Johnson, a Democrat of South Dakota, introduced a bill to name the North American bison as the national mammal. It is hard to think of a better or more deserving creature for that distinction. The bison is already a part of America's official iconography. It appears on the obverse of the buffalo nickel, a much-loved coin minted from 1913 to 1938. And, in hindsight, we can see the tragic parallel between the eagle and the bison. The founding fathers could not have known that the eagle would nearly become extinct, partly because of the spread of DDT. Nor could anyone who saw the immense North American herds of bison imagine that they would nearly be hunted out by the 1880s, which was a disaster for the species, for the ecosystem that bison shaped and for American Indians, who depended on bison. At one time, they numbered fewer than 1,000 animals. Bald eagles have recovered - from 417 nesting pairs to more than 10,000 - and they have done so in the wild. Bison have rebounded, too. But of the nearly half-million now in existence, a vast majority live in commercial herds, and many of them carry genes from cattle. Only about 20,000 bison live in conservation herds, and, of these, only a few thousand - like the herd in Yellowstone National Park - are pure genetic descendants of the millions that once roamed the grasslands. Like the bald eagle, the bison is more than a symbol of our nation. It is a reminder of our responsibility to respect and conserve this country's remaining wild areas and the species that are a fundamental part of them.