Hidden for nearly 100 years for being too "graphic," a report of "hooligan" behaviors, including sexual coercion, by Adelie penguins observed during Captain Scott's 1910 polar expedition has been uncovered and interpreted.

The naughty notes were rediscovered recently at the Natural History Museum in Tring, in England, and published in the recent issue of the journal Polar Record.

George Levick, a surgeon and the medical officer on Scott's famous 1910-1913 expedition to the South Pole, called the Terra Nova expedition, detailed his account of the penguins' seemingly odd behaviors in a four-page pamphlet "Sexual Habits of Adélie Penguins" in 1915. (The expedition, led by Navy Captain Robert Falcon Scott, would arrive at the South Pole to discover that Amundsen had beaten them there.)

"As it was boldly headed 'Not for Publication' it immediately caught my eye," Douglas Russell, who discovered the pamphlet, told LiveScience. "As the curator of birds eggs and nests at the Natural History Museum and having had a long-standing interest in polar research, I knew of George Murray Levick and that this was, as the header suggested, fascinating but totally unpublished work."

During their journey, Levick observed and recorded details on the lives of the Adélie penguin (Pygoscelis adeliae) colony on Cape Adare. He even recorded the very first penguin at the colony — the world's largest of this species — on Oct. 13, 1911.

"Some of the things he noticed profoundly shocked him," Russell said. For instance, Levick noted the penguins' autoerotic tendencies, and the seemingly aberrant behavior of young unpaired males and females, including necrophilia, sexual coercion, sexual and physical abuse of chicks, non-procreative sex and homosexual behaviors. [See Levick's Notes his Penguin Photos]

Considered too explicit for society at the time, the pamphlet wasn't published with the other Terra Nova expedition reports. As such, it remained hidden in the bird collections at the museum to be uncovered recently by Russell.

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"Levick's notes were decades ahead of their time and possibly the first ever attempt to reveal the more challenging aspects of bird behavioral strategies to the academic world," Russell said in a statement.

At the time, Levick was so shocked by what he saw he recorded the events in Greek to disguise the information, at one point writing, "There seems to be no crime too low for these penguins."

For instance, on Nov. 10, 1911, Levick wrote in Greek (translated here): "This afternoon I saw a most extraordinary site [sic]. A Penguin was actually engaged in sodomy upon the body of a dead white throated bird of its own species. The act occurred a full minute, the position taken up by the cock differing in no respect from that of ordinary copulation, and the whole act was gone through down to the final depression of the cloaca."

In another entry, this one written in English on Dec. 6 of that year, he wrote: "I saw another act of astonishing depravity today. A hen which had been in some way badly injured in the hindquarters was crawling painfully along on her belly. I was just wondering whether I ought to kill her or not, when a cock noticed her in passing, and went up to her. After a short inspection he deliberately raped her, she being quite unable to resist him." [Homosexual Tales: 10 Gay Animals]

Levick described penguins that waddled about the colony's outskirts terrorizing any straying chicks as "little knots of hooligans" in his pamphlet. "The crimes which they commit are such as to find no place in this book, but it is interesting indeed to note that, when nature intends them to find employment, these birds, like men, degenerate in idleness."

Homosexual behaviors in animals are no longer cause for hiding data, or even a blush. (Case in point: Dutch biologist Kees Moeliker won an Ig Nobel prize in 2010 for the first report of dead gay duck sex.)

Plenty of animals are out of the closet, so to speak, from dolphins and killer whales to bonobos and greylag geese. Some estimates put the number of animal species that practice same-sex coupling at 1,500.

And while Levick may have viewed the interactions between penguins through an anthropomorphic lens, today that's not the case, the researchers note.

Necrophilia, for instance, is not the same in penguins and humans; Rather than being sexually aroused by a hot gal, male penguins are chemically wired to respond in certain ways to a seemingly compliant female of breeding age.

"I'm very pleased that, 97 years after Levick submitted it for publication, the study has finally been published," Russell said. In fact, no other studies on this colony have been published, the researchers note.

Some 100 copies of Levick's pamphlet were originally printed, though only two are known to exist today.

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