George Murray Levick observed what he saw as necrophilia, homosexual behavior and abuse of young chicks by what he termed "hooligan" males and was so shocked he never formally published his findings.
He only wrote a short account of his observations for a few fellow experts, an account that was then lost for 100 years until it was recently discovered and put on display at the Natural History Museum in Tring, England, the Los Angeles Times reported Monday.
While Levick documented normal sexual behavior of penguins he also observed actions he found so repulsive he wrote his journal notes in Greek so that most other people could not read them.
He wrote of males having sex with dead females, along with homosexual behavior and males having sex with young chicks.
Modern animal scientists say Levick was too prone to judge the birds' behavior in terms of human sexuality.
Researchers since Levick's time have found males respond to specific visual cues that can sometimes lead to inappropriate behavior, particularly when they are young and inexperienced.
For example, they said, a dead penguin lying on its back with its eyes half open would appear to a young, inexperience male to be a compliant, willing female.
Levick's original report and an analysis of it by modern researchers has been published in the journal Polar Record.