Moles hate eating sand, Leicester research reveals

Anyone who has had their day at the beach ruined by the sound and sensation of biting into a sandy sandwich can look to the humble mole for ways of avoiding this unpleasant experience over the summer.

New research from the University of Leicester reveals that the underground-dwelling mammals appear to avoid chewing on sand and earth when eating earthworms because it is likely that they find the sensation as repulsive as humans.

Researchers at the University’s Centre for Palaeobiology Research studied moles from sites across Norfolk to answer the question: does the sandy diet of moles mean that their teeth show evidence of excessive scratching and wear? They discovered that no matter how much sand was in the soil or how much ended up in their stomachs, the scratches, or microwear, on the moles’ teeth remained the same. In fact, there were similarities to the teeth of other small mammals, such as bats, that eat only soft foods, like moths and butterflies.

Professor Mark Purnell, Professor of Palaeobiology at the University of Leicester and a co-author of the study, said: “The findings suggest that, although moles clearly consume sandy food, they somehow avoid crunching and chewing on it, probably because, like us, they find it unpleasant.

“This makes sense biologically: chewing on sand every day would rapidly destroy their teeth. Our results support the idea that we can analyse patterns of microwear as evidence of what an animal has been eating and gives us confidence that we can use it to understand the diets of fossil mammals.”

The researchers also found similarities in tooth microwear in Jurassic fossil mammals from Wales. One of these fossil mammals, called Kuehneotherium that lived 200 million years ago, was previously thought to eat soft, winged insects, but this latest research reveals that Kuehneotherium could have foraged for soft prey within the soil too.

Neil Adams, PhD student in the School of Geography, Geology and the Environment and lead author of the study, explained: “A lot of fossil mammals are only known from their teeth, so it can be difficult to know what they were like as real, living animals.

“From our comparisons of tooth microwear, we were unable to rule out mole-like diets for Kuehneotherium. This suggests Jurassic mammals that lived alongside dinosaurs could have eaten worms, and not just insects as previously thought.”

The paper is published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology.