In a video that was shared recently by an animal enthusiast, two pigs can be seen "using" tools. This is the first documented case of pigs using tools. Shot at a Parisian zoo, two pigs are seen using sticks to dig and build nests. They belong to the critically endangered Visayan warty species. Though many wild species ranging from chimpanzees to dolphins use tools, no one has reported this phenomenon in any of the 17 wild pig species and the domestic swine. This was part of a larger study ‘Concept-specific tool used by Sus cebrifons’ published in the September 2019 edition of the journal ‘Mammalian Biology’. It was conducted by Meredith Root-Bernstein, Trupthi Narayan, Lucile Cornier, and Aude Bourgeois.
A pig named Priscilla captivated Root-Bernstein so much that she along with her team of researchers visited the Paris zoo 2015 onwards on multiple occasions. They wanted to observe how Priscilla and other pigs responded to the tools.
In her observations, Root-Bernstein wrote, "She would deposit some leaves, move them to a different spot on the mound, and dig a bit with her nose. At one point she picked up a flat piece of bark about 10 cm x 40 cm that was lying on that mound, and holding it in her mouth, used it to dig, lifting and pushing the soil backward, quite energetically and rapidly."
In the 2017 trial too, Priscilla dominated the proceedings by using the stick to dig 7 times in total. While the study could not determine why the pigs kept on digging, it had certain landmark observations.
Two female pigs and one male were under observation during the process of nest building. The hypothesis of the research was that the use of the stick to dig could have been learned through vertical transmission, from mother to daughter as well as horizontal transmission from female to male. The stick had a specific placement in the nest-building sequence when handled by the female pigs. Furthermore, this is the first observation of the unprompted tool use by the pigs. The researchers concluded that it was possible to conduct further studies on tool use and social learning among the Visayan warty pig species.