Pigs have been recorded using tools for the first time by a scientist at a French zoo.
Ecologist Meredith Root-Bernstein made the discovery while observing an endangered species of swine at the Jardin des plantes in Paris.
She noticed one of the Visayan warty pigs picking up a stick in her mouth and digging a whole with it.
Further observation confirmed that the animals were preparing nests for the arrival of piglets every six months.
They were even recorded using a kitchen spatula that researchers put in the enclosure as part of their investigation.
Pigs are widely regarded as among the most intelligent animal species, with some research suggesting they can match a three-year-old human child.
However Ms Root-Bernstein discovered there had been no previous reports of the species Suidae - either wild or domesticated – using tools.
“They have many traits associated with tool use, so this is surprising,” she wrote in the latest edition of Mammalian Biology.
Tool use has been reported in several other non-human species, including dolphins, elephants, monkeys and birds.
Wild chimps have been seen teaching their children to use tools to probe for termites and a cockatoo was observed inventing and making his own tool in captivity in Austria.
Ms Root-Bernstein told the National Geographic: “It brings us closer to animals and helps us realise it’s all connected.”