This beautiful animal is Nacho, a Mexican black king snake, a species which in the wild would be found in north-western Mexico.  King snakes are so called because they have the ability to eat other snakes, and they are also believed to be immune to the venom of several types of venomous snake including rattlesnakes. 

The picture of Nacho above was taken in December 2010, whereas the ones below were taken in August 2007 when I first bought him and soon after he hatched - as you can see he has grown a bit since then!!

Mexican black king snakes often start their lives with a little bit of yellow spotting on their jet black scales.  Every time they shed their skin the yellow spotting fades a little, so that by the time they are fully grown the spotting is usually completely gone and the snakes are a pure jet black all over and very beautiful indeed.  The pictures below show how much some of Nacho's  spots have faded in the years between these two pictures being taken:

When any snake is preparing to shed its skin, its colour fades and the skin often takes on a very dull appearance compared to its normal colouration.  Also, the eyes cloud over and often look bluish-grey when they are preparing to shed their skin.  In Mexican black king snakes this is particularly noticeable as you can see from the picture of Nacho below! 

The bluish tinge and cloudiness of the eyes are caused by a build-up of fluid between the old outer skin and the new inner skin.  This fluid helps the snake to shed its skin when the time is right, by allowing it to slide off more easily.