Arthur (1964-2001 aged 37) was a male capuchin monkey who was originally kept as a pet in Somerset. However, he did not have the correct living conditions due to living in a tiny cold shed surrounded by his own waste. He was also an incorrect diet of raw eggs and bread. He eventually lost most of his fur and his teeth became overgrown. Despite this, the local council approved of Arthur's living conditions every year.

In 1999, following his elderly owner's death, Arthur was rehomed at Monkey World. To give Arthur company, the staff put an overweight male ring-tailed lemur named George into his enclosure after the latter was ousted from his group.

Later that same year, Arthur was joined by another male capuchin named Sinbad, who had been rescued from a pet shop in Manchester. The two formed a close bond. The two took a stand against George as he kept eating their food, resulting in the lemur being removed from the enclosure and placed in another one at the park.

In 2001, Arthur and Sinbad were joined by a female capuchin named Terri (who was previously kept as a pet in London). Sadly later that year, Arthur died aged 37.