No, this is where we get the lesser-known “Bison Bob” - semi-famous from wild west stories such as “The Good, The Bad, and the Okay-looking,” and “Fistful of Sand Dollars”
It is set a little before Buffalo Bill and the attempt to eradicate the native Americans by eliminating their food supply: Buffalo. They nearly succeeded in driving the animal extinct. They had little luck eradicating the people
As others have said, these are taken from Gary Larson’s daily website posts of old comics.
He is still drawing. Although retired, he recently got a tablet and has been experimenting with it, so he puts out new comics on his website every so often when the mood strikes him.
I imagine his ultimate nightmare was closer to having his people's land stolen and his tribe whiped of the face of the earth, with little more than a reference regarding their murderers as the sum total of their history.