Lucy the chimp was an animal who settled the issue of nature versus nurture. This is a quandary that has plagued scientists and philosophers since time immemorial; a juxtaposition of biology, animal behaviourism, genetics and anthropology. A search for a complete theory of human nature. Often, the only way for us to understand the differences between environmental and biological factors is to observe our more primitive relatives; the various ape species with whom we share so much of our genetic material.

Apes are a twisted reflection of homo sapiens. They are like us and yet unlike us, so similar in anatomy and cognitive processes, and yet still wild animals utterly removed from many basic conceptions we humans take for granted. Over the years, the observation of chimps by pioneering zoologists, such as Jane Goodall and Francine Patterson, has taught us profound lessons about the way in which these animals understand language and problem-solving.

Lucy the chimp was born in 1964, apparently rescued from a troupe of carnival chimps in Florida. Taken from her mother at a very early age, she was auctioned off to researchers from the Institute of Primate Studies in Oklahoma, USA. Lucy was the subject of numerous scientific studies, but she became especially noteworthy after she was adopted by the renowned psychotherapist Maurice Temerlin and his wife, Jane.

Temerlin wanted to find out if a chimp would adopt human characteristics and behaviours and thus the two of them decided to raise Lucy as though she was their human daughter. Temerlin was clearly interested in the psychology behind primate development, but although he and his wife cared deeply for her, it became obvious that they didn't exactly have the animal's best interests in mind.

Lucy the chimp was given nappies, and even toys to play with and a cot to sleep in. She was taught to eat using cutlery, like a knife and fork, and was served cooked food from the table, dining with her mother Jane and father Maurice. As Lucy grew older her tastes and attitudes refined themselves, in some ways reflecting the development of a human child into an adolescent.

Lucy learned how to dress herself and started wearing human clothes, such as hats or dresses when the fancy took her and enjoyed flicking idly through magazines and staring at the brightly-coloured pictures within their pages, although it was obvious that she could not comprehend their meaning.

By the time she was a teenager, Lucy was indulging in many of the same vices that contemporary teens were enjoying. She developed a fondness for drinking gin, and would sometimes become quite inebriated if left unsupervised for too long. She looked after a small cat which she reared herself and kept as a sort of pet, although the Temerlins were always anxious that Lucy might decide to maul and eat the kitten if so provoked.

Primatologist Roger Fouts was an integral part of Lucy's development, and from 1974 onwards, five years after the Temerlin's adopted her, taught her a very simplistic form of sign language, much like what Patterson would later attempt with far greater success with Koko the female gorilla. Lucy's linguistic fluency and comprehension allegedly improved markedly from chimps in the wild as a result of her living environment. She eventually learned some 250 signs.

It's debatable whether she truly understood language and was capable of really communicating, or whether she was simply aping (pun unintended) human behaviour through mimicry thanks to positive reinforcement and Pavlovian conditioning. But what was apparent was that Lucy displayed a heightened sense of empathy compared with wild chimps. She would even comfort her foster mother if she saw she was distressed, hugging and grooming her without instruction.

As Lucy matured she even reportedly showed signs of sexual arousal when reading playgirl magazine, which meant that she had begun to see human beings as potential mates due to her lack of exposure to members of her own species. At one point she even attempted to masturbate with a vacuum cleaner. It was clear that Lucy's burgeoning libido was causing problems, so the Temerlin's decided to introduce her to a male chimp, so she could mate with him. The encounter was a disaster. Lucy was terrified by the male chimp and was incapable of relating to him. He frightened her into a state of panic. It was clear that she was too alienated from her own kind to even interact with them safely, much less breed with them.

All was not well in the Temerlin household. Lucy was getting unmanageable. She became more and more aggressive and destructive, destroying furniture and tearing up clothes. Although it was clear that she loved her 'parents', and could not begin to comprehend what was wrong with her life, it was clear that she was cognisant of an imbalance, that her state of being was fundamentally irregular, and this wrongness manifested itself as profound angst and dissatisfaction. She even began signing to Fouts that she felt depressed.

Thus, the misguided Temerlin's took steps to try and rehabilitate their adoptive daughter. Lucy was taken to a chimpanzee rehabilitation centre in Gambia, and looked after by psychology graduate student, Janis Carter. Lucy did not acclimatise well to the rehabilitation centre, but in time she was able to interact with the other chimps there and was warily accepted by them. Yet she was not completely content: she remained visibly underweight and still never mated with any of the other eligible males when she was given the opportunity.

A year after living in the centre, Carter came to visit; Lucy embraced her and then knuckled off with the other chimps in tow. Carter took this to mean that she'd finally found acceptance. Another year later Carter returned and found Lucy's corpse. She'd been decapitated and her hands had been hacked off. Carter suspected poachers, but the truth has never been proven conclusively.

The 1970s were clearly a different time for experimentation with animals, but even bearing this in mind, the actions of the Temerlin, as well as the other scholars and researchers involved, seems remarkably naive and irresponsible. Lucy was an animal caught between two worlds. The experiment had been a failure. She was no longer an ordinary ape, but still far from human. A thing apart. A square peg jammed into a round hole. A backwards Tarzan. The loneliest creature on earth.