A search for more information about the now-extinct eastern cougar yielded a variety of cites (and sites), including this one, which speaks to the problem of vanishing species 155 years ago -- from Henry David Thoreau's March 23, 1856 journal entry:
I spend a considerable portion of my time observing the habits of the wild animals . . . By their various movements and migrations they fetch the year about to me . . . But when I consider that the nobler animals have been exterminated here, the cougar, panther, lynx, wolverene, wolf, bear, moose, deer, beaver, turkey, etc., etc., I cannot but feel as if I lived in a tamed and, as it were, emasculated country . . . Would not the motions of those larger and wilder animals have been more significant still? Is it not a maimed and imperfect nature that I am conversant with? . . . When I think what were the various sounds and notes, the migrations and works, and changes of fur and plumage which ushered in the spring, and marked the other seasons of the year, I am reminded that this my life in nature, this particular round of natural phenomena which I call a year, is lamentably incomplete. I listen to a concert in which so many parts are wanting . . . Many of those animal migrations and other phenomena by which the Indians marked the season are no longer to be observed . . . I should not like to think that some demigod had come before me and picked out some of the best of the stars. I wish to know an entire heaven and an entire earth. All the great trees and beasts, fishes and fowl are gone; the streams perchance are somewhat shrunk.