Beheading is prescribed punishment in the Koran, much like stoning is in the old testament.
I'm glad to see the Saudis moving up so quickly. Not 10 years ago they were about where the west was in the 1200s. They've already moved all the way up to the 1600s! Before you know it, they'll be in the 1800s and will reintroduce slavery.
What is it with Muslims and cutting off body parts?
Muslims in the Middle East, specifically.
The Middle East is today in the same period of cultural evolution as Europe was in the Middle Ages. Maybe someday they will have their Renaissance and Enlightenment.
Personally, I suspect that the Middle East Enlightenment could come sooner if the population of the region were forced to deal with other cultures via in-person trade and the widespread usage of communication technology like the Internet. These things tend to have a homogenizing effect on a culture.