Although the two chimera piglets died within a week of being born, both were found to have DNA from macaque monkeys in their heart, liver, spleen, lung and skin.
They were bred from more than 4,000 embryos which were implanted into a sow using IVF, according to the New Scientist.
A team from the State Key Laboratory of Stem Cell and Reproductive Biology in Beijing genetically modified monkey cells to produce a fluorescent protein allowing the researchers to track the cells and descendant cells.
These modified cells were injected into the pig embryos five days after fertilisation.