Crystal River, Fla.

No, they are not seals or sea lions. Manatees, or sea cows, as they are sometimes called, are aquatic mammals that can grow to 13 feet and over 3,000 pounds, even though they eat only plants.

No one knows how many live in the Gulf of Mexico, the Amazon Basin, West Africa’s coastal area, the Caribbean Sea or their other habitats, but scientists have counted as many as 3,300 in Florida, and we had been promised that some were in the waters now beneath our boat.

From November through March, Crystal River, 70 miles north of Tampa, is the epicenter of manatee-watching. The manatees cannot survive in water below 60 degrees