Extinct wolf ( Canis dirus ) that existed during the Pleistocene Epoch (1.8 million10,000 years ago), probably the most common mammalian species found preserved in the La Brea Tar Pits .
It differed from the modern wolf in being larger and having a more massive skull, a smaller brain (and probably less intelligence), and relatively light limbs. The species was considerably widespread; skeletal remains have been found in Florida and the Mississippi valley in the U.S., as well as in the Valley of Mexico.