Piggy Eaters: Boars Wash Their Food

You may think that pigs will eat anything, but think again. It turns out that many porcine diners are actually picky eaters and will only enjoy a meal after it's been properly washed.

That's at least according to a study recently published in the journal Animal Cognition, which details how even the hungriest wild boars will always wash their food before eating as long as there's a fresh puddle or stream on hand.

This revelation, of course, flies in the face of the common adage "dirty as a pig," but it shouldn't come as much of a surprise. Farmers raising domestic hogs will likely tell you that the animals can be pretty selective about what kind of slop they are happy being served, and like with other animals, the livestock industry has learned to cater to their tastes - all the better to fatten them up.

The 'dirty' habits of pigs as well, such as wallowing in mud, is actually for a very healthy and hygienic purpose. When a pig covers itself in mud, it is essentially looking to keep itself clean of fleas and other insects, while simultaneously cooling off. Surprisingly, as pigs branched from the same evolutionary lineage as hippos and even whales, they do not have sweat glands.

This latest study simply adds to the list of these 'dirty' animals' cleanly behavior. Researchers observing European wild boars (Sus scrofa - a species currently experiencing a population explosion in the wake of climate change) determined that as long as there was water nearby, the pigs would wash their food before eating. (Scroll to read on...)

This proved true for apples, beetroot, and even chunks of chicken - something first observed by zoo keepers at Basel Zoo in Switzerland. [You can watch a bizarre slideshow of the boars in action here.]

To test how common this behavior was, researchers then ran several experiments. In one scenario, boars were presented with clean and dirty food. Predictably, the animals ate the clean food immediately. However, when they found dirty food among the clean, the pigs stopped to wash it in water first, without fail. This even proved true when the animals were forced to skip breakfast, meaning that they were willing to endure hunger pangs just to maintain clean eating habits.

Study author Adriana Lowe from University College London recently told BBC News that one of the pigs even drooled over his apple first, washing away sand with spit because he was "too lazy to go to the water" where his comrades were.

So why are these pigs being such careful eaters? Lowe and her colleagues suggest that this is actually all about tooth care, where chewing on sand could cause some irreparable damage to the animals' chompers.

The researcher add that unfortunately "we were unable to ascertain to which degree individual and/or social learning brought this behaviour about," but they hope to next observe it even among purely wild populations.

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