Animal-made art is art created by an animal. Animal-made works of art have been created by apes, elephants, cetacea, reptiles, and bowerbirds, among other species. Painting animals Pigcasso the pig Pigcasso is a South African pig that has gained international notoriety for her abstract expressionist paintings, which have sold for thousands of dollars around the world. Pigcasso was rescued from an industrial hog farm as a piglet by her owner, Joanne Lefson, who taught her to paint using positive reinforcement techniques. Lefson uses the proceeds of the sales of Pigcasso's paintings to raise funds for her farm sanctuary in Franschhoek, South Africa. Each of Pigcasso's works is signed by means of the artist dipping her nose-tip into beetroot ink and touching it onto the canvas. Pigcasso and Lefson are the first non-human/human collaboration to have held an art exhibition together, which took place at the Victoria & Alfred Waterfront in Cape Town in 2018. Three of Pigcasso's most famous pieces are Peacock, Snowman, and Mouse, each of which sold for $5000 in 2021. A painting of Prince Harry that was sold to a Spanish buyer for over $3000 in 2021 also received global notoriety, based on its royal subject matter. Pigcasso's most expensive work sold in December 2021 for $27000, making it the most expensive animal-made art piece ever to have been sold at the time. Primates During the late 1950s biologists began to study the nature of art in humans. Theories were proposed based on observations of non-human primate paintings. Hundreds of such paintings were cataloged by Desmond Morris. Morris and his associate Tyler Harris interpreted these canvas paintings as indications of an intrinsic motivation toward abstract creativity, as expressed through an exploration of the visual field and color. Many of these painters progressed over time by expanding or contracting the area of paint coverage, the horizontal or vertical stroke relationships, and even the development of content. Such paintings were exhibited in many modern art museums during the late 1950s and early 1960s. The cultural and scientific interest in these paintings diminished steadily and little note is taken today. The most successful chimpanzee artist is Congo (1954–1964). Morris offered him a pencil and paper at two years of age, and by the age of four, Congo had made 400 drawings and paintings. His style has been described as "lyrical abstract impressionism". Media reaction to Congo's painting abilities were mixed,