Taharat
The anus and buttocks may be cleansed with toilet paper or similar paper products, especially in many Western countries. Elsewhere, water may be used (using a jet, as with a bidet, or splashed and washed with the hand). In other cultures and contexts, materials such as rags, leaves (including seaweed), corn cobs, sponges or sticks are used.
The use of water in Muslim countries is due in part to Muslim sharia which encourages washing after all instances of defecation. Further, Islam has made flexible provisions for when the water is scarce that the use of stones or papers can equally be practiced for the act of cleansing after defecation as well as in ablution. The use of these other means to clean one's self doesn't include animals bones or skin in consideration to these being food for other animals and non-human creatures. In many countries, a hand-held bidet or pail of water is used in lieu of a pedestal.
http://en.wikipedia.org/wiki/Anal_cleansing
http://www.islam-laws.com/taharatandnajasat.htm
