It was a herbivore
it probably used them for stripping bark off trees or for scratching that hard to reach spot on the middle of the back.
( Undulating Tentacles of Love getting fun down to acceptable levels, Mon 11 May 2009, 10:49, archived)

Or flicking the bean
of a very, very smelly female.
( Goatworrier had your mum and she was shit, Mon 11 May 2009, 10:58, archived)

or poking smaller dinosaurs in the eye

( spangolin - the odds are good but the goods are odd, Mon 11 May 2009, 10:58, archived)