Legend has it that centuries ago, manatees(海牛) used to be mistaken for mermaids, so a sight last week at one Florida state park would have put ancient sailors in shock.

Blue Spring State Park is home to one of the largest winter gathering sites for manatees in Florida, and recently, the park reached a new record when the number of manatees spotted in one group was nearly 1,000.

Manatees typically flock to the park during the winter months. According to a Facebook post from the non-profit Save the Manatee Club, January 21 was one of the coldest mornings of the Florida winter season so far. The temperature of the St. Johns River, which Blue Spring sits on, was recorded at 14.9℃.

To survive the cold winter weather, manatees will seek out water that is typically warmer than 20℃. This is because despite their thick-looking bodies, the blubbery animal affectionately known as the sea cow only has "about an inch of fat and a very slow metabolism(新陈代谢),meaning they cannot easily stay warm," says the state park.

Since their spring water remains at a constant 22.2℃, and is protected from human recreational activity, Blue Spring makes the perfect manatee shelter during the colder months. "What's more, many manatees rely on artificial warm water sources from power plants, and these might be going offline in the near future. So having some of these manatees come to these natural warm water sites and finding them is really encouraging," says Cora Berchem, a research associate and the director of multimedia at Save the Manatee Club.

According to the Florida Fish and Wildlife Conservation Commission, there are anywhere between about 7,000 to 11,000 manatees in Florida, which represents a large increase over the past 25 years.