Pigs can get painful sunburns because their skin is very sensitive to the sun.

Pig skin and human skin are very similar. Both have a thin layer of hair and react to ultraviolet rays in the same way. When the sun hits a pig's skin, it can cause DNA damage, redness, and blisters. This is a major problem for light-colored pigs like the Large White breed.Pigs cannot sweat like humans to stay cool. They lack the sweat glands needed to release heat through their skin. Rolling in mud helps them lower their body temperature by about 2 degrees Celsius. This is more effective for them than sweating would be.The mud acts as a physical barrier against the sun. Once it dries, it blocks UV rays just like the zinc oxide found in human sunscreen. Without mud or shade, pigs can suffer from second-degree burns. These burns cause the skin to peel and blister.Farmers often provide mud pits or shade to keep their animals safe. Some even use special sunscreen made for animals. Because pig skin is so similar to ours, scientists use it to study how to treat human burns and skin diseases. Research in 2011 confirmed that wallowing in mud is a biological need for pigs to survive in heat.