U.S. surgeons transplant pig heart into human patient
You might be asking, why a pig? I don't know, but forever ago I wrote software for a cardiovascular imaging lab and pigs were their primary test subjects. I was like, "why pigs?" and the PI was like, "Imaging-wise, pig hearts aren't too different from humans. Plus, we can give them a heart attack in the scanner and not go to jail. Some labs use dogs. I just can't do that."