I have 2 young gerbils (males) named Louie and Moe. I got them a few weeks ago and they are so cute! However, I don't feel like I'm doing a great job of taming them. they don't like being handled and always try to squirm away when I hold them. Sometimes they even nip me(it doesn't hurt very much, but it's still not nice). How do I get them used to human company??