Hisan, a seven-year-old gray Caspian mare made history at the Memphis Zoo August 15 by giving birth to Xerxes, the first Caspian horse born in a U.S. zoo.

Named after predecessor of King Darius the Great of Persia, Xerxes (ZERK-CEES) was born at 6:40 p.m. The young colt was born weighing approximately 45 pounds.

“I didn’t get to see him drop, but I was there for the rest of it, said Farm keeper Tracy Dunlap. “He was walking within 20 minutes.”

Xerxes is the first Caspian horse born in a zoo, with Memphis being the only zoo in the country to exhibit this rare breed. Since their introduction into the U.S. in 1995, only 114 (now 115) Caspians live in the country, and there are fewer than 500 horses worldwide