Humans have no stress without the prehistoric killers beasts https://www.britannica.com/animal/dire-wolf
Dire wolf, (Canis dirus), wolf that existed during the Pleistocene Epoch (2.6 million to 11,700 years ago). It is probably the most common mammalian species to be found preserved in the La Brea Tar Pits in southern California. The dire wolf differed from the modern wolf in several ways: it was larger and it had a more massive skull, a smaller brain, and relatively light limbs. The species was considerably widespread, and skeletal remains have been found in Florida, the Mississippi Valley, and the Valley of Mexico.
Dire wolf (Canis dirus) from Rancho La Brea, Calif.; detail of a mural by Charles R. Knight, 1922.
Courtesy of the American Museum of Natural History, New York