Rolling through the back of the Vassar Campus, watching a murder of crows on the lawn, when all of a sudden:
That squirrel passed about three feet in front of Mary’s bike, running flat out and, at 60 frame/s, touched the ground every 200 ms:
Figuring a squirrel body+tail is 1.5 ft long and it covers 3 of those units with every leap, it’s moving at 22 ft/s = 15 mph. That’s about as fast as we travel…
The Smell of Molten Projects in the Morning 
If you looked tasty to a hawk, you’d move fast, too. We have jackrabbits, and one lost its head to an owl (probably Great Horned) last summer. The survivors are rather fast. I’ve seen foot prints every 8 feet or so in the snow when they get going. Our dogs are too old to join the hunt, but they’ll go nuts in their kennel when they see see the rabbits.
Lost only its head? That may explain last summer’s mystery. I found a full-grown cottontail inside my fenced garden. It was intact but for a missing head. There /are/ owls in the vicinity.
A Bing search says they like to go after the BRAAAAAAAAINS!! for the nutritional value. [grin]