The story of ‘humanzee’: how scientists tried to create a new human species

The Soviet biologist Ilya Ivanov became the inspiration for Professor Preobrazhensky in Mikhail Bulgakov’s science fiction novel Heart of a Dog. In the book, the genius doctor accidentally produces a man out of a stray dog when a rejuvenating experiment goes wrong. In real life, Professor Ivanov tried to create a hybrid of a human and chimpanzee, or ‘humanzee’. But he was not the only one to go along that path. How successful were these experiments?

Ilya Ivanov specialised in the field of artificial insemination and the breeding of different animal species. His method of artificial insemination of farm animals is used today. Most of all, however, the Soviet scientist was inspired by the idea of breeding a human-ape hybrid. Ivanov was sure his experiments could significantly advance science. Moreover, he supported his theoretical knowledge with practical results: he produced hybrids of donkey and zebra, domestic cow and bison, interbred a cow with an antelope, and significantly improved horse-breeding. He openly announced his intention to interbreed a man with an ape at the International Congress of Zoologists in Graz in 1910.

Experiments in Africa and first failures

In the 1920s, the newly formed Soviet Union tried to undermine religious thinking and justify its deliberately technocratic society’s superiority. Ivanov decided his time had come as the country began to recover from the devastation of the civil war. In September 1924, he applied to the People’s Commissariat for Education to sponsor his daring experiments at the research station in Africa. The French agreed to provide him with a station in French Guinea. The Soviet authorities supported the project, and the money was allocated.

In 1924 Ivanov, accompanied by his son, a biologist, arrived at the research station in French Guinea. Unfortunately, upon arrival on the island, it turned out that there were not enough adult chimpanzees on the station, so the experiment had to be postponed for another six months.

Eventually, the Governor of Guinea permitted Ivanov to work in the botanical gardens of Conakry. The scientist arrived there in November 1926. On February 28, 1927, two female chimpanzees caught by local station employees were fertilised with human sperm obtained from male volunteers. On June 25, another monkey was fertilised in the same way.

A story with an unhappy ending

In July 1927, Ivanov and his son left Africa with thirteen chimpanzees. By then, it was clear the first two monkeys had never gotten pregnant. The third died in France, but it was not pregnant at the time. In his report to the Academy of Sciences, Ivanov pointed out the experiment failed, but this, of course, does not mean that crossing is fundamentally impossible. The problem was the experiment was conducted under challenging conditions, and by mid-1927, Ivanov had run out of funds. The Academy of Sciences did not agree to finance his operations. The scientist had to take the fertilised and other monkeys to the Sukhumi Nature Reserve in the USSR, where his experiments would continue.

“It is necessary not only to increase the number of experiments of artificial insemination of female chimpanzees with human sperm but also to conduct experiments of reciprocal cross. The latter is much more difficult to organise in Africa than in Europe or here (in the Soviet Union). Women willing to undergo the experience are easier to find in Europe than in Africa. For this kind of experiment, it is enough to have 2-3 adult male anthropomorphic monkeys,” the biologist wrote.

Two years later, in Sukhum, Abkhazia, he organised an experimental group. The commission decided that at least five female volunteers would be needed for the experiment. The only problem was the only primate in Sukhum, an orangutan had died. A year later, a new batch of monkeys was scheduled to arrive, and this was exactly what the scientist was waiting for.

Ivanov was arrested and sent into exile, where he worked for two more years before his death from a stroke. In an obituary published in one of the scientific journals, Ivanov’s experiments on crossing a man and a monkey, which he considered almost the most essential thing of his life, were mentioned very sparingly, in just one sentence. Thus, ended the attempts of Soviet science to create the ‘humanzee’.

Other experiments in ‘humanzee’ breeding

Gordon Gallup, one of the leading experts in evolutionary psychology, spoke to the media about a unique project US scientists worked on in the 1920s: interbreeding chimpanzees and humans. Gallup claims the experiment was very successful.
The experiment was conducted by scientists at the Orange Park Laboratory in Florida, where one of the first primate research centres was located. Here, a female chimpanzee was inseminated with human sperm. As a result, the animal not only became pregnant but gave birth to a living being. However, the cub did not live long, and then it was euthanised for ethical reasons. Gallup was told about the birth of the ‘humanzee’ by his university professor, who had worked at the Orange Park laboratory.

Another recorded case occurred in China in 1967. A female primate became pregnant with a hybrid but died after scientists were forced to abandon the project.

Oliver walked on his hind legs. He had no hair on his head and chest. Many believed it was a hybrid of a chimpanzee and a human and had 47 chromosomes (humans have 46 chromosomes, and chimpanzees have 48). However, in 1996, a DNA test showed Oliver was a very ordinary chimpanzee with 48 chromosomes. The primate lived to be 55 years old and died in 2012.

Is it possible to breed a ‘humanzee’ at all?

J. M. Bedford, Professor Emeritus of Reproductive Biology of Weill Cornell Medical College in the 1970s, researched the early stages of fertilisation, particularly the penetration of sperm into the egg, to develop male contraception. He injected human sperm into the eggs of various animals — from hamsters and saimiri monkeys to the smallest of the great apes — gibbons.

Bedford was surprised to find that human sperm has a very high degree of specificity: the only egg the sperm penetrated was a gibbon. That is, it belonged to our most distant relative among the anthropoids.

When asked what would happen to a chimpanzee egg, he suggested a positive result. “Given that they are closer to a human than a gibbon, it is likely that chimpanzee sperm would be able to fertilise a human egg, and vice versa”, Bedford said.

He explained that live juveniles are born sterile in some hybrid combinations, but sometimes not; in other cases, the embryos begin to develop and then die during pregnancy. “I can’t predict whether the resulting embryo will survive. We may never know if humans and chimpanzees hybridise”, he noted.