Why is Surfs Up a PG and not a U?

[chicaguapa]

Does anyone that has been to see it know? DD is going through a stage of being scared of things! She has nightmares about Barbie and Magic of Pegasus but doesn't mind the shark in Finding Nemo!

They say 'crap' and we didn't watch all the way to the end but there's a bit of cartoon violence, where a big penguin beats up a littler one.