i got a baby guinea pig about 3 months. i already have a 5 month old boy guinea pig (both males). when i put them together the older one sniffed the new guinea pig and sniffed his chest. when he was sniffing the new ones chest it looked like he was nibbling the younger one. normal? when i put them in the cage, they were walking around together and then the baby jumped at the older one. then i separated them. is this normal? what are normal and abnormal things to look for? should i still introduce them? thanks