ST ANDREWS, Scotland (Reuters) - Students dressed in costumes chased each other with shaving cream in a massive foam fight at the University of St Andrews on Monday, as part of a decades old tradition for newcomers.

Each year, freshers at the Scottish university, where Prince William met his now wife Kate Middleton when they were both students, join so-called academic families where they are adopted by older students for mentoring.

Several weeks into the first term, the university holds its annual "Raisin Weekend", during which the academic parents hold parties for the new students. The weekend culminates in "Raisin Monday", when they dress the new students in costumes and send them into the university main's lawn for a shaving foam fight.

(Writing by Marie-Louise Gumuchian; Editing by Alison Williams)