Oliver the chimp
Oliver (c. 1958 – 2 June 2012) was a former 'performing' ape once promoted as a missing link or 'humanzee' due to his unusually human-like appearance and a tendency to walk upright. Despite his somewhat unusual appearance and behavior, scientists determined that Oliver was not a human-chimpanzee hybrid. Wikimedia

One hundred years ago, a chimpanzee-human hybrid - known as a humanzee - was born in an American lab, according to the claims of renowned evolutionary psychologist Gordon Gallup.

Panicked doctors euthanized the baby soon after the experiment due to ethical concerns and fear of the word getting out, Gallup told the Sun, recounting the reports of his former university professor who had worked at the US's first primate research centre, in Orange Park, Florida, during the 1920s.

"They inseminated a female chimpanzee with human semen from an undisclosed donor and claimed not only that pregnancy occurred, but the pregnancy went full term and resulted in a live birth" Gallup said, describing his professor's account.

"He told me the rumour was true. And he was a credible scientist in his own right," added Gallup - the creator of the famous mirror test which proved that primates are capable of self-recognition.

There is some debate as to whether a humanzee would be scientifically possible, although some researchers think a viable hybrid is not beyond the realms of possibility given that we share the vast majority of our DNA with chimps.

While no humanzees have ever been confirmed, a number of unsuccessful attempts have been reported.

Most notably, Soviet biologist Ilya Ivanov tried and failed to create a human-chimp hybrid in the 1920s. Similarly, reports emerged in the 1980s that scientists in Maoist China had impregnated a female primate with human sperm in 1967, only for the ape to die of neglect after the researchers were sent to labour camps in the midst of the Cultural Revolution.