Passage: They also lived in Beringian North America during the Pleistocene. Today, the dominant subspecies (S. t. tatarica) is only found in one location in Russia (in the Republic of Kalmykia and Astrakhan Oblast) and three areas in Kazakhstan (the Ural, Ustiurt, and Betpak-Dala populations). A proportion of the Ustiurt population migrates south to Uzbekistan and occasionally Turkmenistan in winter. It is extinct in the People's Republic of China and southwestern Mongolia. It was hunted extensively in Romania and Moldova until it became extinct in those regions at the end of the 18th century. The Mongolian subspecies (S. t. mongolica) is found only in western Mongolia.

Question: In which period did the Ustiurt live?
Pleistocene