The tiny Key deer, a subspecies of the white-tailed deer, survives in the far-off reaches of Big Pine Key and is protected at the 8,000-acre refuge. Best times to spot one of the 800 or so deer is on a slow drive during the morning or evening hours. Visit the refuge’s Blue Hole (a lake formed by quarry digging) to see alligators, turtles, and fish in the see-through waters and hike two self-guided nature trails.