Filmmaker Dave Meinhart did not expect puppy Pegasus to live long, having saved her from a careless breeder. Poor Pegasus has a condition which leaves most puppies afflicted with it lined and death. Pegasus was the only one of her litter who’d survived and wasn’t deformed by the time they’ve got to.
He was determined to document her life, no matter how short it was. The result is this video; she managed to make it all the way to adulthood, and Dave recorded her doing her daily exercises on the treadmill.