I'll recomend that you check
Guinea Lynx :: A Medical and Care Guide for Your Guinea Pig before considering adopting a GP. This is not a 1 year pet. They live 7-9 yrs, and they required a special care like vitamins and excersise, but if you are 100 % sure that your cats and dogs won't get to them, then you may find a person willing to give it to you in adoption.