Manatee

day 1, camping trip to Blue Spring State Park
Blue Springs, (one of the many natural springs in central and northern Fla.), flows into the St. Johns River, north of Orlando
Since the spring maintains a 72F temperature year-round, the manatees congregate there when it is warmer than the surrounding waters (in the winter). They feed in the river during the day (unseen in the darker water, except when they surface to breathe), and return to rest in the spring run for the night.
We saw at least 50 there this time, some very close- even right under the dock. But they're hard to photograph, looking down on them in the water. Their faces are only visible from the side.