How do pigs sweat?

They have no sweat glands and therefore cannot sweat. Why this is so is not entirely clear. It is probably a trait that was slowly filtered out genetically over time to reduce the threat of...

Pigs can not sweat because they have no sweat glands. They roll around in the mud to cool their skins.

No. Pigs do have sweat glands but they do not function like a human's does. They can release a little water and heat through passive diffusion, but it is not enough for the pigs to rely on. So in...

A pig only has one sweat gland, the nose

Because they don't need them, because mud and water are available to them year round.