New caledonian crested gecko

Question
I have a 12 year old gecko and it's tail fell off? Any idea why ? Thanks

Answer
Geckos will drop their tails to divert a predator.  Is their any other animal or perhaps a child that might have frightened him?  Your gecko is only middle aged so their is a good chance it will grow back.  Just give him good food and no stress.  You may want to have him checked by his vet about two weeks after the tail dropped to make sure the scare that made him drop the tail has not caused a rise in gut parasites.