so, given that you know it's a common kingsnake, you should know that imitating a rattle snake is a pretty common defensive behavior for just about all snakes occuring in the NA rattlesnake range. So, don't worry. To make it a little bit tamer, the best advice is frequent gentle handling. Try not to approach it from behind or directly above, don't restrain it too much, and don't reinforce it's defensive behavior- that is, when it makes this show, confidently but gently handle it to teach it that those behaviors will not work. If it bites, it doesn't hurt at all unless the snake chews in in a feeding response, and even if it does, it's not very bad at all. But the most serious factor is just the snake getting used to it, so keep handling it for just 5-10 minutes a day regularly. As it grows, it will settle down. I've also seen an improvement in the behavior of my cal king come from feeding it in a separate place, like a large cardboard box, supervised of course. best of luck!
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-Chris
cdohna.googlepages.com
1.0.0 WC SD Gopher Snake, Max
1.0.0 CB Albino Banded Cal King, Manny
0.1.0 CB BRB, Mucalinda
0.1.0 CB BP, Maya