Persian Gulf flooding of the basin started 15,000 years ago due to rising sea levels of the Holocene glacial retreat. This inland sea of some is connected to the Gulf of Oman in the east by the Strait of Hormuz; and its western end is marked by the major river delta of the Shatt al-Arab, which carries the waters of the Euphrates and the Tigris. In Iran this is called "Arvand Rood", where "Rood" means "river". Its length is , with Iran covering most of the northern coast and Saudi Arabia most of the southern coast. The Persian Gulf is about wide
Persian Gulf 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