They are big and chunky. They have very thick and wrinkled skins, just like elephants. And they weigh up to 1,300 pounds and grow almost as long as walruses. Well, that does not mean they are fat. In fact, unlike other sea mammals such as whales and dolphins, manatees don’t have blubber—the extra layer of fat that keeps animals warm.

What is blubber?

Blubber is a special layer of fat under the skin of animals that acts as a jacket. It is efficient in holding body heat, enabling aquatic animals to stay warm even in winter. Not all marine animals have blubber layers. While whales, seals, dolphins, walruses, sea lions and polar bears have blubber, animals such as sea otters and manatees have no blubber and have to use other means to keep warm when winter sets in. But for manatees, the situation is made even worse by their slow metabolism and slow movements, which make it hard to generate heat on their own.

Perpetual migrants

Without blubber, manatees have no protection against cold. And neither do they like it when water temperature falls below 68 degrees. Actually, manatees suffer cold stress and hypothermia when the surrounding water gets colder than 68 degrees Fahrenheit. Which means they get sick and eventually die from prolonged exposure to severe cold. And so to survive in winter, they migrate to warmer water areas, which include the natural springs where the water is always 72 degrees, the relatively warm shallow canals or the water outflows near power plants.

Thermal refuges

Manatees migrate into warmer waters every winter to stay warm when temperatures of surrounding waters drop below 68 degrees Fahrenheit. The thermal refuges for manatees are natural warm water springs that remain at a constant 72 degrees during winter and the artificial power plants that pump warm water into coastal areas, creating warm places where manatees can spend winter months.

The bubbling springs retain their temperature throughout the year. And so while the 72 degrees all-year temperature of the springs feels cold in the summer, it is warm in the winter and comfortable for manatees. That is why hundreds of them are usually huddled together in the springs during cold months. For those who want to see the manatees, winter provides a great opportunity because the animals are gathered in their hundreds in the springs making it easier to find and observe them.

Danger of relying on power plants

When municipal and private power plants pump out warm water into surrounding ponds and canals, they create ideal conditions for survival of manatees during winter. Actually, up to 60 percent of manatees spend their winters clustered around power plant outflows. But since manatees learn to move to warmer waters from their mothers, some young ones may only end up going with their mothers to outflows near power plants and may never know where warm natural springs are. The problem with this is that should a power plant be turned off for whatever reason, the manatees will still go to the power plant location during winter. And if there is no warm water, they will still stay by the power plant and end up dying.

Record deaths from cold stress

Manatees are tropical or near-tropical animals without blubber or other means of staying warm. When water temperature falls below 68 degrees, they become sick and can die. For instance, many young manatees died when Florida had severe cold weather in late 2009 to early 2010. The cold lasted too long and made it hard for the animals to leave their refuges and travel through the cold water in search of food. More than 400 manatees died—a record number—most from cold stress and hypothermia.

Want to know more about manatees and how they behave? Already in love with manatees and want to see and swim with them? Or would you like a private or group manatee tour in Crystal River under the supervision of a licensed guide?

At Captain Mike’s Swimming with the Manatees, we cherish these animals and work towards their preservation and survival. So we provide information about them and offer manatee friendly tours in their natural habitat. Book your tour with us and set yourself up for a splendid outing with the sea giants. For more information on manatees and manatee tours in Crystal River, Florida, visit the site “Captain Mike’s Swimming with the Manatees“.