In 1051 at Goslar, a town in what is today Germany, a group accused of heresy was examined by ecclesiastical authorities. The heretics:

"were finally condemned when one of the bishops, more zealous in his presentation of the case than mindful of the dignity of his rank, presented them with a live chicken and ordered them to wring its neck. They refused to kill the bird, and were deemed beyond hope of redemption. Ignoring the arguments and threats of the assembly, they refused to recant and were hanged upon a gibbet."

The execution of these heretics, as near as can be determined by modern scholars, was ordered because it was felt that "their attitude implied a dualist-type belief in the transmigration of souls through the animal kingdom" and suggested that they were Manichaeans. The events at Goslar — and this group was not alone among persecuted Christian groups in the eleventh century C.E. in its refusal to kill animals — are often treated by scholars as an important step toward the twelfth century full-blown assault on heresy by the Church linked to the newly proclaimed death penalty for heresy.

The researchers ran an experiment on three plots of land spread out across the Spanish countryside. One plot was sprayed daily with the smelly essence extracted from the scat of ferrets on a beef-based diet. Another plot was sprayed with the scat odour from ferrets on a rabbit-based diet. The third was sprayed with water as a control. Every few days, the team counted the rabbit pellets left behind on the plots and used the number as an indicator of how often rabbits were visiting the plots to feed.

There were fewer pellets in the plots sprayed with rabbit-based scat odour than in those sprayed with the beef-based scat odour, suggesting the rabbits were avoiding places where it appeared other rabbits were being eaten.