One of the more unusual marine mammals living in the Persian Gulf is the dugong (Dugong dugon). Also called sea cows, for their grazing habits and mild manner resembling livestock, dugongs have a life expectancy similar to that of humans and they can grow up to in length. These gentle mammals feed on sea grass and are closer relatives of certain land mammals than are dolphins and whales. Their simple grass diet is negatively affected by new developments along the Persian Gulf coastline, particularly the construction of artificial islands by Arab states and pollution from oil spills caused during the Persian Gulf war and various other natural and artificial causes. Uncontrolled hunting has also had a negative impact on the survival of dugongs. After Australian waters, which are estimated to contain some 80,000 dugong inhabitants, the waters off Qatar, Bahrain, UAE, and Saudi Arabia make the Persian Gulf the second most important habitat for the species, hosting some 7,500 remaining dugongs. However, the current number of dugongs is dwindling and it is not clear how many are currently alive or what their reproductive trend is. Unfortunately, ambitious and uncalculated construction schemes, political unrest, ever-present international conflict, the most lucrative world supply of oil, and the lack of cooperation between Arab states and Iran, have had a negative impact on the survival of many marine species, including dugongs.