I forgot to bring my camera when we went to Batu Cave and I fully regret it when I saw these monkeys playing around, jumping on people.  One of them tried to grab the banana out of a tourist's hand, and a woman almost fell off the stairs trying to avoid the kind of aggressive monkeys while her husband's taking their groufie, and the rest were just puzzled.  

I took these using my phone.  We were not able to climb up the stairs going to the cave though because they don't allow people wearing shorts and flip flops, but you can wear sarong which are available right at the entrance.