In each of these events, animals died rapidly due to hypothermia.
Manatees can also die as a result of sustained exposure to cold.
In these situations, the temperature is not cold enough to cause acute hypothermia, but rather these animals waste away. Animals suffering from prolonged exposure generally have not been eating properly and become skinny from malnutrition. Some of these animals have noticeable whitish patches of skin on the muzzle, throat, chest, and flippers, possibly related to reduced blood flow to the skin surface. Sadly, studies indicate that juvenile manatees appear to be the most frequently affected by hypothermia. These young animals are apparently not experienced enough to realize that they need to move to warm water refugia.