Arthur Schubarth, 80, illegally imported parts of the world's largest species of sheep from Kyrgyzstan, which he used to create cloned embryos in the United States.

The resulting fetuses were then implanted in ewes on his Montana ranch, resulting in the birth of a genetically pure Marco Polo argali, an endangered species that can weigh more than 300 pounds (135 kilograms) and has horns more than five feet (1.5 meters) wide.

Schubarth then used semen from this specimen to impregnate various species of sheep in an effort to create never-before-seen hybrids, with a goal of making even larger sheep.

He hoped to sell the resulting animals to "canned" hunting ranches, facilities where customers pay to shoot captive animals, and where bigger animals can command higher prices.

"This was an audacious scheme to create massive hybrid sheep species to be sold and hunted as trophies," said Assistant Attorney General Todd Kim of the Justice Department's Environment and Natural Resources Division, who prosecuted the case.

"In pursuit of this scheme, Schubarth violated international law and the Lacey Act, both of which protect the viability and health of native populations of animals."

The Lacey Act prohibits interstate trade in certain wildlife and is used by authorities to combat wildlife trafficking.

Schubarth, whose ranch breeds and sells mountain sheep, mountain goats and other ungulates primarily for game ranches, admitted one count of conspiracy to violate the Lacey Act, and one of substantively violating the Lacey Act.

The felonies carry a maximum penalty of five years' prison and a fine of up to $250,000.