"Tribes that bury their dead in kurgans (which are so common over vast geographic and temporal expanses) have been migrating into India throughout its history, but these have not induced language shift across the entire north of the subcontinent. So one is hardly compelled to interpret the scanty evidence of the Bishkent and Vakhsh cultures as evidence of the arrival of a new language group on its way to Indo-Aryanize North India. Like the Andronovo culture, this culture does not enter the subcontinent either. Moreover, Piankova (1982) dates the graves to the last quarter of the second millennium, which is far too late for migrants who are supposed to already have completely settled down and written the hymns in the Indian subcontinent by this time, even allowing the lowest possible dates proposed by scholars for the Rgveda. Moreover, anyone prepared to gloss over the absence of horse bones in these sites cannot then deny the presence of the Indo-Aryans in the Indus Valley Civilization on these particular grounds."