WHY IS MY GUINEA PIG SHY/AGGRESSIVE?

I've had my abbysinnian guinea pig for 4 years and he's always been really shy/aggressive.
Whenever someone walks past his cage, he goes running to his hiding igloo. Also, when people walk past him and go near him, he starts teeth chattering.
He never bites and has never bitten anyone and when people get him to cuddle, he seems to enjoy it.
Can any guinea pig owner please explain this and how to make him less shy/aggressive?
Thanks :))))))

Anastasia2014-12-15T17:24:28Z

Just like humans since some of them are outgoing while some are shy, it applies to the guinea pig also. You just have to tame it a little bit more even though you had it for four years. Encourage it to come out of it's igloo by giving it a treat or hand feed it some food for it to get used to you. It may possibly work and your guinea pig might not hide anymore once a human goes near it's cage. Imagine a giant that is probably ten times your size coming near you. It thinks that we are predators that are trying to harm it. Just make your guinea pig know that you are friendly and will not hurt it.

Tiffany2014-12-15T15:56:48Z

I've had a few guinea pigs and I've been in this same position. When he hides it's because there's a giant (to him/her) human walking near my home so he hides. It's a natural instinct. All you can do is try to be more social with him/her. Get it out more. Play with it. Let it run around in a ball.

Caine Breedlove2014-12-15T15:57:57Z

Because hes a small animal? guinea pigs are like that. and he doesnt seem agressive