Domesticated rabbits come in all sizes and colors, including tiny Dutch dwarfs, French floppy ears, Flemish giants, and fluffy angoras.
These breeds are among Europe’s only rabbit species, originally restricted to the Iberian Peninsula and southern France, and used as meat and fur animals since the last Ice Age, culminating in domestication around 1,500 years ago.
On the other hand, there are many species of rabbits in America, with areas of distribution on both continents. The archaeological records show that rabbits were used as widely in America as they were in the Iberian Peninsula, with clear archaeological evidence that rabbits were purposely bred. Then why were rabbits domesticated in Europe and not America?
Recent work by archaeologists Andrew Somerville of Iowa State University and Nawa Sugiyama of UC Riverside has found a simple answer: European rabbits willingly live in large social groups while American cottontail rabbits do not. The less social character of the American cottontails combined with greater biodiversity resulted in a situation where rabbit farming did not lead to domestication.
Sugiyama looked to Teotihuacan, a major city in Mexico, about 2,000 years ago, where cottontail rabbits made up 23% of animal remains during the Classical Period. This was more than any other animal used for meat, including wild deer, as well as domesticated turkeys and dogs. The proportion of rabbit bones increased towards the city center, suggesting that they were likely raised rather than hunted.
Rabbits were buried at the sun and lunar pyramids and can be found in the stomach contents of carnivores such as eagles and pumas. Rabbit bones found in the stomachs of carnivores contain a type of carbon that indicates an unusually high corn or cactus diet, suggesting that human-raised rabbits were in turn fed to the carnivores.
“The rabbits were likely fed corn, but the carbon isotopes don’t differentiate between corn and cactus, so we can’t say for sure,” Sugiyama said.
In addition, 46% of animal bones unearthed in a residential building were from rabbits fed a diet similar to that of agricultural crops, and the amount of phosphate in the floor of a room indicates a place where rabbits urinated and were likely housed. A stone statue of a rabbit was also found in the central square of the complex, highlighting the importance of keeping rabbits to residents.
A thousand years later, the 16th century Spanish conquistador Hernan Cortez described the sale of rabbits in the Aztec marketplace of Tlateloco. However, for at least a millennium of keeping and extensive use for food, fur, and rituals, the rabbits of Mexico have not been domesticated – a reciprocal, intergenerational relationship characterized by human-controlled reproduction.
To understand why, Somerville compared the behavioral ecology of European rabbits and American cottontails to criteria that “prepare” or prepare animals for domestication. Animals that have been domesticated usually live in groups with resident males. They also have cubs who mold themselves easily and require parental care, a promiscuous mating system, tolerance to a variety of environments, and low reactivity with people.
European and American rabbits were similar for all criteria except conduct. European rabbits live in underground family structures called warrens of up to 20 individuals, including males, who defend their breeding area from other males. Warrens made it easy for humans to locate and manage wild rabbit populations, and then mimic those captive conditions where rabbits reproduce easily.
American cottontails, on the other hand, are loners, live entirely above ground, and tend to fight together in enclosures. Males do not defend breeding grounds and pursue more opportunistic mating strategies.
Somerville and Sugiyama conclude that their loneliness, inclination to fight in enclosures, scattered territories, and less predictable mating systems made it possible to breed rabbits without forming the kind of mutual relationship that eventually gives humans enough control over one species would give to control their evolution. Greater biodiversity also made it less likely that any of them would have been domesticated.
The open access paper “Why Were Rabbits of the New World Not Domesticated?” Is published in Animal borders and available here.