Pigs and their Love Affair with Mud

It is a true picture of contentment, and now a scientist is suggesting that a pig's love of mud is more than just a way to keep cool. A researcher in the Netherlands has looked at wallowing behavior in pigs' wild relatives to find out more about what motivates the animals to luxuriate in sludge. His conclusions suggest that wallowing is vital for the animals' well-being. So, instead of pigs needing to cool down in mud because they do not have functional sweat glands, Dr Bracke thinks that they "did not evolve functional sweat glands like other ungulates because they liked wallowing so much".  http://news.bbc.co.uk/earth/hi/earth_news/newsid_9464000/9464994.stm