Some Rams Prefer Other Rams

New studies presented by researchers at Oregon State University which show that about 8 percent of rams are "male-oriented", may have the potential to help explain sexuality in other mammals, including humans.

The findings, by researchers at Oregon State, Oregon Health & Science University and the U.S. Department of Agriculture’s Sheep Experiment Station, suggest that homosexuality may be biologically driven, a hot topic in the perennial "nature vs. nurture" debate

Fred Stormshak, professor of animal science at Oregon State, states that researchers found marked differences in the brain anatomy and hormones between male- and female-oriented rams.

"In rams who like other rams, the anterior preoptic area of the hypothalamus was about half the size of this part of the brain in heterosexual rams," he said

"This was exciting to us because this area of the brain has been found in many species to regulate sexual behavior," Stormshak told The Gazette-Times of Corvallis.

In 1991, neuroscientist Simon LeVay reported he had found a key difference between the brains of homosexual and heterosexual men he studied. LeVay showed that a a part of the brain that is believed to control sexual behavior - was, on average, more than twice the size in heterosexual men as in homosexual men.

"We're after a basic biological understanding of how the brain works, and the neurons that drive sexual behavior," said Stormshak.

The ram study began in 1995, when researchers at the federal Sheep Experiment Station in Dubois, Idaho, noticed that some rams refused to mate with female sheep. Of these animals, some showed no interest in males or females, and a fraction preferred to mount other rams.