Hundreds of manatees are making their way to the Three Sisters Springs in Crystal River, Florida, to seek protection from the cold waters in the Gulf of Mexico, according to CNN. Almost 400 of the big marine mammals, which weigh half a ton and can span up to 13 feet long, can be seen crowding into the 72-degree waters of the springs, as shown in the video below.

"It's almost like a bear hibernating in a cave," said Ivan Vicente, a visitor services specialist with the U.S. Fish and Wildlife Service. "They do sleep for over a whole day. When they do wake up, there's very minor movements and very little activity, and then they just go back to sleep."

One of the main reasons that this refuge is so important is because cold water stress can be fatal for manatees, and even those that are at the Three Sisters Springs can lose a considerable amount of weight. In order to protect the mammals, which are currently endangered but may soon be removed from the list, the Fish and Wildlife Service has closed off the area to humans in order to help them seek refuge.

The site will remain closed through Tuesday and may reopen Wednesday if the cold weather subsides, although current cold weather forecasts may lead to the number of manatees seeking refuge in the area to hit 500.

In addition to the cold weather, Laura Ruettiman, an educational guide at the Springs, says that the rise in manatees seeking protection in the area is likely due to a combination of the greater protection offered by the area as well as habitat loss in other areas of the state, according to Time.

"We have a record number this year," she said. "We have 150 more manatees here than have ever been recorded in the past."

Approximately 5 percent of Florida's manatee population, which currently sits at 6,000, according to Inside Edition, has died from cold stress thus far.