My sister owns female brindle black rat snake. The snake was 2 years old when she bought her in the winter of 2009-2010. She is my sister's only snake and has not interacted with any other snakes since my sister bought her. She is at least 5 feet long. In the spring of 2011, she laid a total of 16 eggs over a period of a couple weeks. Is there a precedent for this? What would cause this to happen? We sure were confused!