Did monks first tame rabbits, after a pope declared foetuses seafood? Scientists don’t swallow it

The story of how rabbits supposedly became domesticated animals is a strange one.

Around the year 600, the tale goes, Pope Saint Gregory the Great issued a papal edict declaring that fetal rabbits were not meat. Because fluid-filled amniotic sacs surrounded rabbit foetuses, they counted as fish. Eaten this way the rabbits were a delicacy – a snack called laurices.

French Catholic monks, who abstained from meat while observing Lent, pounced on the opportunity. Monks began to breed the animals like, well, rabbits. Skittish wild animals went into the monastery. After a few generations, out came tame and fluffy pets.

This story was plausible enough. The location made sense: wild European rabbits from the Iberian Peninsula and France are the closest genetic relatives to pet rabbits. Greger Larson, a biologist at the University of Oxford who studies domestication, recalled hearing about Pope Gregory at a conference a few years ago. The rabbit genome had just been sequenced.

The problem, as Larson and his colleagues discovered, is the story isn’t true. “It turned out that the whole thing was a house of cards,” he said.

Larson did not set out to debunk a legend. In fact, his initial goal was to find proof of its date. Researchers like Larson use rates of mutation, in a method called a molecular clock, to estimate the age of domesticated species. But this method comes with baked-in ambiguities. If rabbits had a known domestication date, Larson could use the timeline to improve these molecular methods, like setting a watch to an atomic clock. He asked archaeologist and computer scientist Evan Irving-Pease, then working on a master’s thesis, to hunt down a copy of the papal document or any supporting information.