Every year more and more people live near the warm coasts and rivers that are also the homes to manatees and dugongs. Manatees and dugongs have fewer places to live and feed. This loss of living space, or habitat, is a major threat to the future survival of these gentle animals. Other threats are caused by the changes people bring to the shallow waters where manatees and dugongs live. For example, in the United States, some people drive boats carelessly and too fast. Manatees are not quick enough to get out of the way and they are killed or injured badly by boat's hull and sharp propellers. Notice the scars on the back of the manatee in the picture. Some people chase or tease the animals. Some people discard fishing gear and other trash into the water. Manatees and dugongs accidentally eat this or become entangled in it and die. Floodgates and canal locks sometimes kill the animals by trapping them under water and causing them to drown. Pollution kills the seagrass and other plants which manatees and dugongs eat.