In 2015, Meredith Root-Bernstein, a conservation ecologist, was watching a family of Visayan warty pigs – a critically endangered species native to the Philippines – at a zoo in Paris. She noticed that an adult warty pig named Priscilla used a stick to dig a hole. Root-Bernstein instantly became fascinated with how the pig used the tool to build a nest. Together with other researchers, they returned to the zoo several times over a few years.
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In those years, Root-Bernstein and her team manipulated elements in the exhibit to see if and how Priscilla and the other pigs would react to the tools. “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,” she said.
|Photo Credit: CNN|
What’s even more interesting is that pigs aren’t known for nest-building. According to an article by CNN, an American news-based pay television channel, they are also not known for using any tools. People might think that they are just into rolling around the dirt, but a recent study published in Mammalian Biology suggests that pigs can use tools, too.
During Root-Bernstein’s visit, she observed that the pigs didn’t do anything with the tools they brought. However, in 2016, the researchers saw that Priscilla and her female offspring moved the sticks in a rowing motion to dig and build a nest. Billie, Priscilla's mate, also dug with a stick. However, it failed since his attempts were clumsy compared to his female members. They also noticed that the pigs digging with sticks were less ineffective compared to their usual digging with their snouts or hooves.
|Photo Credit: CNN|
The researchers concluded that the pigs were using the tools as a reward. Aside from that, they learned that the pigs study each other to learn behaviors. “We might think that only humans manipulate the environment to affect their own lives, but in different ways, many other species do this too,” Root-Bernstein said.