SUMMERTON — The carcass of a manatee was found this week on Lake Marion, where the creature apparently died of cold exposure.

State wildlife officials are surprised the manatee managed to slip unnoticed through the locks at the Lake Moultrie dam and make it 100 miles inland — the most likely explanation for the rare appearance in Lake Marion. It appeared to be an adult manatee and likely was the same one spotted on the lake several weeks ago, said agency spokesman Brett Witt.

The S.C. Department of Natural Resources got various reports over the past six weeks of possible manatee sightings in Lake Moultrie and in Lake Marion. While agency biologists thought it was possible for a manatee to maneuver through locks and diversion canals at the dams for the two lakes, they thought it was unlikely, Witt said.

DNR officers who patrol the lake never saw the manatee alive.

Responding to a report of a carcass near Camp Bob Cooper in Clarendon County on Tuesday, officers found the dead manatee, and they pulled it from the lake on Wednesday. A necropsy will be done to determine the cause of death, but cold temperatures are suspected, Witt said. Manatees can’t survive long in water temperatures below 60 degrees. Air temperatures reached the low 30s in the area this week. The water temperature in diversion canal between the two man-made lakes is 55 degrees today.

Manatees are marine mammals that spend their lives near the coast, thriving in salt or fresh water. They feed off aquatic plants. The North American species is found mostly in Florida, though individuals often drift north into coastal waters in the Carolinas.