By Calif law, if your are at least 16 you are required to have a DFG Calif State Fishing License to possess WC Cal kings, gophersnakes, etc. And possess means holding in your car or on your person. With a license, you can have 4 Cal kings or 4 gophersnakes or 2 of each or 1 of one and 3 of the other.. get it? You can have only 2 rosyboas. Check the Dept of Fish & Game website or just read the fishsing license. The rules are there.
BTW, WC can mean wildcaught but not always. It just means the king didn't come from someone with a Breeder's Permit. If someone gives you a Cal king they found, you still need the Fishing License. If someone gives you a Cal king they hatched (without a breeder's permit), you still need a Fishing License.
You need to apply for and be accepted for a Reptile and Amphibian Breeder's Permit to sell or keep any offspring you produce.
If you buy or receive these animals from a breeder with a breeder's permit, you can have as many of those as you like as long as you have the receipts if challenged.
If you bulldoze an empty lot and kill all the kings, you don't need a fishing license..
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Mark