He described this behaviour as "depraved".
His report was considered too shocking for public release, and it was suppressed until 2012.
According to scientist Petter Bøckman: "No species has been found in which homosexual behaviour has not been shown to exist, with the exception of species that never have sex at all, such as sea urchins and aphis."
animals proven to have bisexual behavior
Courtship, mounting, and full anal penetration between bulls has been noted to occur among American Bison.
The Mandan nation Okipa festival concludes with a ceremonial enactment of this behavior.