The Zebu is a bull native to the Indus Valley, in what is now India and Pakistan.  Many theriomorphic (animal-shaped) drinking vessels of this sort have been found in the Gilan province of northwestern Iran. The Elamite civilization spanned Mesopotamia, Persia and Babylonia, and there was constant contact between the civilizations. The rhyton may be related to the Persian cult of Mithras, which involved the sacrifice of bulls as tribute to this sun god.  According to mythology, Mithras battled the Bull of Heaven, an embodiment of the natural world, and as a result of his victory human civilizations were granted successful harvests.