Paypal's official policy is that their claims handling excludes the sale of live animals. I haven't run into this myself, but I have seen it come up time and again where a buyer gets stiffed after paying through Paypal and they ask here on the forums what to do about it, the general response is "Paypal MIGHT help, but they don't offer buyer protection on animal sales." They'd probably just as soon not get involved in animal transactions, likely for the reason you're describing, it's too easy to be less than honest about what it means to be a "satisfied customer" when you're talking living things rather than dry goods.