When someone finds a human body, investigators estimate the time since death by comparing it with other bodies—but sometimes the best comparisons available are what happens to animal carcasses, not human ones. Entomologists have even testified in court about human decomposition based on evidence from pigs. But can animals really stand in for humans when justice is on the line? To find out, researchers monitored the decomposition of five human, pig, and rabbit carcasses in a wooded area near Knoxville, Tennessee, on three separate occasions: in spring, summer, and winter. Recording how quickly different body parts on each carcass decayed, they added them up into a measure called “total body scoring.” In the spring and summer, when there were more insects about, the nonhuman animals decomposed faster than humans. But in the winter, humans decomposed much more rapidly than pigs—likely because scavengers like raccoons and robins went for the humans first. The findings, presented at the American Academy of Forensic Science meeting in February, are preliminary, and the researchers are still preparing their work to be submitted to a peer-reviewed journal. But the stark differences in the way that human and nonhuman carcasses break down casts doubt on experts who estimate the time since a human’s death from animal carcasses—and the study’s results could one day be used in court to argue against those experts’ testimony.