Historical documents deemed too shocking for their time have been unearthed, detailing the "astonishing depravity" of penguins.

According to The Guardian, Dr. George Murray Levick, a surgeon and medical officer on the 1910-1913 British Antarctic Expedition, Terra Nova, found himself appalled by the behavior of penguins at the colony of Adelies at Cape Adare. The Terra Nova was led by Captain Robert Scott.

Levick carefully documented his journey, but his four-page pamphlet, written in 1915, on the perversions of penguins was considered so shocking it wasn't published with the other Terra Nova expedition reports.

Now, thanks to Douglas Russell, curator of birds at the Natural History Museum in London, Levick's report, entitled "Sex Habits of the Adelie Penguin," has been discovered and reveals his total disgust for these animals and their ways.

In a press release, Russell states that Levick's time spent in Cape Adare makes him the only scientist to this day to have studied an entire breeding cycle. Levick was horrified by the actions of "hooligan males" and "observed and commented on the their sexual activity, autoerotic behavior, the behaviour of young unpaired males and females including necrophilia, sexual coercion, the sexual and physical abuse of chicks, non-procreative sex and homosexual behavior."

Witnessing what he believed to be males penguins having sex with dead females was too much for Levick, who wrote down his observations in Greek, fearing the reactions it might produce if read back in England. "There seems to be no crime too low for these penguins," Levick wrote.

Russell and his team of researchers have reinterpreted Levick's observations and published the study in the Cambridge University Press journal Polar Record.

"Levick's notes were decades ahead of their time and possibly the first ever attempt to reveal the more challenging aspects of bird behavioural strategies to the academic world,' said Russell in a press release from the Natural History Museum.

Nearly a century later, researchers aren't quite so prudish when it comes to the study of natural history. In the last 50 years, researchers have become more open to objectively interpreting sexual behaviors in animals, and same-sex behaviors have been documented frequently in many animals and other birds, explained Russell.

Also, modern researchers understand that many of the acts Levick thought he witnessed, such as necrophilia, could be reinterpreted when cast to the bird species. Research shows that, when mating, female penguins will adopt a receptive postion -- lying on their front with their feathers close to their body and eyes nearly closed -- and may appear as though they are dead. Penguins are chemically wired to respond to a seemingly compliant female of breeding age, rather than being sexually aroused.

"Levick tended to anthropomorphise the birds, but they are not little people and we have to interpret their behaviour in the context of zoology," Russell explained to The Telegraph.