Though tigons were previously thought to be sterile hybrids, as with ligers, in rare cases they can produce progeny. This second-generation hybrid is called a li-tigon if the tigon mates with a lion, and a ti-tigon if the tigon couples with a tiger. One ti-tigon, Nathaniel, was born at the Shambala Preserve in California. The story of Nathaniel's unlikely conception mirrors the story behind other big-cat hybrids: Keepers had assumed Nathaniel’s tigon mother was sterile, so they figured it was safe to house her with a male Siberian tiger.