What differentiates anal rapists from vaginal rapists?

During the daily assessment routine of the Federal Documentation Centre for Sexual Offenders, important differences between rapists who commit their offense through anal penetration and other rapists became apparent. The hypothesis following these findings assumed that these and offenders would show a more sexualized behaviour than other rapists. The following differences between these two groups could be shown: violence and hypersexual desire. And rapists show a significantly higher degree in both areas, whereas, on the other side, no difference concerning psychopathic behaviour of the offenders could be proved. The preliminary conclusions that could be drawn according to these results express that anal rapists are more sexualized and, furthermore, they have a more obsessive sex life.