By Mike CherneyThe Daily Northwestern

Two Northwestern biologists say they have solved the mystery surrounding an elusive wild ox that is a focus of international conservation efforts and Cambodia’s national animal.

The answer: It doesn’t exist.

“The kouprey – there really isn’t one,” said John Mordacq, a lecturer in NU’s biological sciences program who co-authored the study.

Mordacq worked with Gary Galbreath, the associate director of NU’s biological sciences program, and F.H. Weiler of Cambodia’s Forestry Administration on an article that was published in July 2006 in London’s Journal of Zoology.

The report stated that the kouprey, rather than being a separate species, is a hybrid between two ox species.

“They have built an awfully strong case,” said Larry Healey, director and curator of the division of mammals at the Field Museum in Chicago, who was not connected to the NU study. “I don’t see any other way to interpret their data right now.”

Although other recent studies have said the kouprey is a separate species, debate rages around the animal’s classification, which was first documented in Cambodia in the early 20th century.

“People wanted to believe in the kouprey,” Galbreath said, adding that a purported set of kouprey horns could fetch $1,000 in Cambodia. “To a lot of Westerners, it was magical and mystical.”

In the NU study, the researchers compared DNA extracted from a kouprey skeleton with that of banteng oxen – another wild ox that has been domesticated across Southeast Asia. They obtained the banteng DNA from the hair roots of two animals housed in a wildlife rescue facility in Cambodia.

The result of the comparison, the researchers said, was that the kouprey DNA was nearly identical to that of the banteng. This suggested that the kouprey was a hybrid between the banteng and another ox species, perhaps the zebu, which has also been domesticated across Asia.

Another study in 2004 did a similar comparison and concluded the kouprey could not be a hybrid because the DNA did not have enough similarities. But Galbreath said that study compared the kouprey DNA with banteng DNA from Java, an island in Indonesia. He said if the kouprey were a hybrid, it would be descended from banteng in Cambodia, not in Indonesia.

Galbreath also said that earlier studies, done in the 1960s, compared physical attributes of kouprey, banteng and zebu and determined the kouprey seemed to be a mix between the two other ox species. But Galbreath said the older study did not get much attention.

In the NU study, the researchers used mitochondrial DNA, found in part of the cell responsible for energy production. This DNA is passed from the mother to offspring and remains relatively unchanged from generation to generation, unlike DNA found in a cell’s nucleus. That makes mitochondrial DNA an excellent tool for determining ancestry, he said.

The researchers have since obtained specimens from five more Cambodian banteng, and Galbreath said their initial sequencing seems to confirm the earlier NU study.

Healey, of the Field Museum, said the implications of the study would be important. Many conservation organizations have specific conservation plans for the kouprey, and if the study is further confirmed, they would have to radically change those strategies.

“This is a very interesting example of the importance of using modern techniques and basic fieldwork to go back and look at something that has been a very longstanding problem,” he said.

“It will emphasize to the public and to the scientific community that we have to continue to do a lot of careful, basic research about these kinds of animals.”

Reach Mike Cherney at [email protected].