In 2012, Douglas Russell of the Natural History Museum in London, UK unearthed a paper called "Sexual Habits of the Adélie Penguin". It was labelled "not for publication".
The paper was the work of George Murray Levick, Scott's expedition scientist and the first person to witness an entire breeding season. He was shocked by what he saw: gangs of males engaging in homosexual sex, sexually abusing chicks, and mating with dead females. At the time, the material was judged too depraved for public consumption.
http://www.bbc.com/earth/story/20151223-if-you-think-penguins-are-cute-and-cuddly-youre-wrong
https://www.bbc.com/news/science-environment-18370797