The details of how most animals became domesticated lie deep in the murky past, much debated and glimpsed only in tantalizing hints from fossils and DNA.

Except for rabbits.

Their story was clear, and it was a strange and compelling tale. Around 600 A.D., Pope Gregory the Great decreed that fetal rabbits, or laurices, were not meat, and could be eaten during Lent, when meat was not allowed. Monks in France — where else? — quickly saw an opportunity and began to keep and breed rabbits as a meaty non-meat to nourish them through a cold and fishy Lent.

Lent, a period of penance and self-denial for many Christians, begins Wednesday, but anyone to whom this story suggests a new menu should stop right there. Apart from the scarcity of laurices at the supermarket these days, the whole story is wrong according to a new scientific report. “None of it is even close to being true,” said Greger Larson, one of the main authors of the report debunking the myth.

“The whole thing is a house of cards,” Dr. Larson said, acknowledging that he too has cited the story just like many other researchers. The remaining question, he said, is: “Why did we never question this? Why were we so willing to believe in this origin myth?”