Recent research shows that rabbits are able to digest and reabsorb calcium from their teeth. (Image credit: Wirestock/Getty Images)
Scientists say rabbits may eat small pieces of their teeth while chewing their food, which means each meal could contain a significant amount of calcium.
Rabbits need a lot of calcium because their teeth — like those of squirrels, beavers and kangaroos — are constantly growing. Researchers previously thought that wild rabbits deliberately chose calcium-rich foods, such as leafy greens, to support this growth. However, new research suggests that they may not need it to meet their mineral needs.
High-fiber diets cause rabbits to chew and grind their teeth constantly. The resulting tooth powder may provide a constant source of calcium, which is reabsorbed during digestion, creating a vicious cycle that endlessly supports the rabbit's tooth growth, according to the study.
“It has been assumed that rabbits would have high mineral requirements, particularly calcium,” the researchers wrote in a paper published in the February issue of The Veterinary Journal. “However, this assumption does not take into account the fact that tooth wear is finely ground tissue that is not lost by the body but is ingested during food processing.”
To find out whether tooth wear could be a source of calcium for rabbits, the scientists conducted a two-week experiment with eight female European rabbits (Oryctolagus cuniculus). The rabbits were fed pellets containing either a standard calcium supplement or ground-up rabbit teeth, and their absorption was measured by analyzing their feces.
The results showed that rabbits are able to digest and absorb calcium from their teeth. In fact, they probably get slightly more calcium from their teeth than from their food, according to the study.
Fecal analysis showed that rabbits fed the tooth powder diet absorbed 33% of the calcium they ate, compared with 20% for rabbits on the standard supplement. The researchers noted that there were no significant differences in average water intake, body weight, or fecal output between the two groups.
Pet rabbit food typically contains calcium to compensate for the fact that pets cannot independently select foods high in calcium. However, new evidence suggests that we may be giving our pet rabbits too much calcium, researchers say.
It was previously believed that wild rabbits
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