Their natural predators are large sharks, saltwater crocodiles, and killer whales. Threat to Manatees and Dugongs Manatees Warm water is necessary to the survival of the manatees. If they remain in the cold waters of the Gulf of Mexico, they are susceptible to a respiratory illness, which is the most common natural cause of death for manatees. This is not the leading cause of death, however. More than 90 percent of manatee mortalities are due to collisions with speedboats.
Many manatees have visible scars from propeller cuts in their flesh.
When awake, they scare easily at the sound of boat motors, but still have trouble finding safety. Click here for Manatee Mortality Statistics. In the United States, manatees are an endangered species. According to Save the Manatee Club, Inc. , there are about 2,600 manatees left in the United States. According toSave the Manatee Club, Inc., it is difficult to tell if this number is the result of an increase in population or if this number will soon decline.