If you have ever taken a dip in one of Florida's springs then you know that water in the low 70s is not warm. Manatees migrate to the springs during the winter just for that very reason, the water is warmer than the rivers they live in during the rest of the year. Florida's springs are diminishing rapidly due to excess pumping. Silver Spring's used to be the biggest spring in the world based on an output of over 500 million gallons per day. It's now less than half that. Manatees can't reach Silver Springs anyway due to the dams placed on the Ocklawaha River years ago, in fact manatees are routinely killed by trying to make it past the locks and spillways at the Rodman Dam. If you are interested in helping protect Florida's springs and waterways then I encourage you to research the issue and take a stand. The St. Johns Riverkeeper website or facebook page is a great place to start.