Manatees

Think of Florida diving and a number of things might come to mind. The Keys of course, for coral and wrecks; next you might think of the area around Fort Lauderdale for more adventurous wreck diving; then central Florida for caves. But move west and north a bit to Citrus County and something different is on offer. The Gulf waters here are shallow - 30 to 60 miles from shore you might just be able to stand head above the waves (OK, not quite), so sea diving is limited but inland there are some attractions along two rivers, the Crystal and the Homosassa. Crystal River is about 80 miles north of Tampa.
These rivers are warm in the colder winter months, with the inflow of vast quantities of spring water, and this warmth attracts manatees. Manatees, if you don't know them, are the large, friendly and endangered marine mammals also known as sea cows (they are herbivores!,) and just possibly the largest marine mammal you could ever have a chance to interact with. This area of Citrus County may be the only place you can do that interacting. In most areas where manatees occur any interaction is strictly forbidden. Here years of strict conservation measures and enforcement of regulations on interactions have found no detrimental problems with personal interaction. So snorkelling / swimming with them is acceptable as an educational (to us humans) endeavour.
Requirements: Swimwear. Snorkel and fins useful, light wetsuit suggested. Nearly anyone can participate (no need to even swim, so open to the whole family). Water temperature is 25°C but you can be in the water a long time, hence a 3 to 5 mm wetsuit.
What happens: The manatees are free-roaming, looking for food over many miles of waterways which meander through both built up and "natural" areas. In the evenings, as it becomes cooler, they congregate at known warm spring heads for the nights. The tour and other boats will try and find them at these locations in the early morning before they again disperse to feed. If not found, or if a bit late, the boats go looking in other likely areas. Once seen, anyone on the boat was welcome to quietly slip into the water at a short distance away and quietly swim near to them. Then it became the manatees option to come and inspect us, which usually they did.
Interactions were personal and very real! A manatee, maybe all 3 m and 1000 + kg, would come and nuzzle up wanting to be scratched. If you obliged and gave them a good scratch, particularly under the front flippers, they would want more and more, moving a metre away then back, rolling over on their side or back, nudging you from the other side. Its almost embarrassing how a 1 ton animal can be so graceful and controlled in the water compared to us, but you'll see it and feel it as they stop next to you, on their side, and lift a flipper for one final scratch before heading back to feeding.
This might be a point to make a comment about the boats generally used for the manatee watching and for at least some of the diving. If you're used to British style RIBs or Red Sea style vessels, the boats used here on calm shallow rivers are a bit different, more like flat pontoons with an outboard. Easy to board, just not elegant!
Yes this was great fun and educational. Everyone I talked to enjoyed it tremendously.
We dived with Birds Underwater based in Crystal River they offer a variety of such encounters. Crystal River has many boats all touting for this tourist trade of manatee watching, but many will only have this, while Birds Underwater goes on to offer diving as well.