Even though humans and chimpanzees are both part of the great ape or hominin family (that also includes the bonobo or pygmy chimp, two species of gorilla and three species of orangutan), they are very distantly related.
It’s estimated the ancestor species of us both split between 5.4 and 6.3 million years ago, and in that time, humans have lost one pair of chromosomes (or in fact, two pairs have fused). So, we now have 23 pairs of chromosomes and chimpanzees have 24, making compatibility for breeding, even by artificial insemination, almost certainly impossible.
- They use tools, fight to the death and live in social groups – and are the closest living relative to humans
- Great ape guide: learn all about the different great ape species, where they live and what they eat
Has anyone tried interbreeding humans and chimpanzees?
In a word, yes. In the 1920s, and with the blessing of the relatively new Communist Government, a Russian biologist called Ilia Ivanov artificially inseminated three female chimpanzees he had captured in Guinea in West Africa, but to his disappointment (though not surprisingly) they all failed to conceive.
Ivanov also recruited women in the former Soviet republic of Abkhazia to be inseminated with male chimpanzee sperm. Remarkably, five women actually volunteered, but his chimpanzees all died, and soon he was only left with a 26-year-old orangutan called Tarzan, who also then died as well.
Is that the only effort?
Possibly not. In the 1980s, reports emerged from China that researchers had tried to fertilise a chimpanzee with human sperm two decades earlier. A scientist claimed in an interview with a Shanghai newspaper that a ‘humanzee’ (as such a creature has been referred to) could be used for simple tasks such as livestock herding, working in mines or exploring space or the deep sea.
It was claimed that a female chimp was three months pregnant, but this has never been verified. The work was apparently stopped in 1967 following Chinese leader Mao Zedong’s Cultural Revolution.
Is there any scientific basis to this work?
A report in the Baltimore Sun in 1981 quoted Li Guong of the Academy of Science as saying interbreeding would be possible “because according to general biological distinctions, [chimpanzees] and [humans] belong to the same category.” But the idea that the two species were sufficiently related to be able to produce offspring together was treated, in the west, with “fantasy and humour”.
What about the ethical issues?
Generally speaking, most people would view the idea of trying to produce a hybrid animal of humans and chimpanzees (or indeed humans and any other animal) as repugnant. This issue was explored in a British TV series called First Born, which aired in 1988. In the series, a scientist played by Charles Dance successfully impregnates a female gorilla (as opposed to a chimpanzee) with donor sperm and raises the resultant male offspring, called Gordon or Gor, as his own son. The boy feels increasingly alienated as he grows into a man. He eventually discovers the truth, meets his mother (the gorilla) and is then beaten to death by her in her cage. The programme was derided by some critics for its clichéd depiction of a mad scientist.
So, in short, humans and chimpanzees cannot interbreed?
Well, not now – but a paper published in Genome Biology in 2006 concluded that after humans and chimpanzees cleaved from each other around 6 million years ago, they continued to interbreed for at least 1 million years.
As the eminent scientific journal Nature put it, the split was more a “messy divorce rather than a clean break, leading to the controversial theory that our two sets of ancestors may have interbred many thousands of years after first parting company.” So we could interbreed in the past – but a very, very long time ago.
