Two cloned mules that were entered in a race in Nevada, US, with naturally bred animals failed to take the top prize.
Idaho Gem and Idaho Star took part in the 20th annual Winnemucca Mule Races, Show & Draft Horse Challenge on Sunday.
The equines won their heats but could only take third and seventh places behind Bar JF Hot Ticket, which came in two-and-a-half lengths clear.
It was the first time the cloned mules, born in 2003, had taken part in a professional race.
"I think both animals, especially Idaho Gem, showed they have a lot of upside," said Don Jacklin, an Idaho man who helped finance the cloning project. "They both proved they could compete," he told the Associated Press.
The scientific team led by the University of Idaho also declared itself satisfied with the outcome.
"Winning the race on the track is important, but the most important race is to find cures for human health," said lead researcher Gordon Woods, who wants to use cloning technology to investigate the causes of disease.
Idaho Gem was the first clone of any animal in the horse family, and the first clone of an animal which cannot normally reproduce. Mules are hybrids - the product of the union of a female horse and a male donkey - and are generally sterile.
Idaho Star (L) and Idaho Gem (R) were created in 2003
Gem and his brothers - Star and Utah Pioneer (which did not race) - were all cloned from the same skin cell line taken from a 45-day-old mule foetus.
The first cloned horse, called Prometea, was born in 2003. Thoroughbred racing is strictly controlled - it does not permit artificial insemination or any kind of fertility treatment.
Gem and Star, who were competing for an $8,500 (£5,800) purse in the finals of their class, were watched by a crowd of 1,000 people at the oval track in Winnemucca, about 260 km (160 miles) northeast of Reno.