How do Black Night percentages work?

I’ve been looking at getting into the Black Nights because there’s just something so appealing to me about an all black animal, but I was wondering if someone could explain how the percentages work. I have a vague idea about how they work but I’m not 100% and I’d like to know more before I jump into anything. An example is that I’ve found a gecko that’s 87.5% Black Night and 12.5% Bold. I know that each percentage is how much of that bloodline is in the animal I’m just not sure how someone comes up with that number. If anyone could explain and teach me about it I’d love to hear it.


Melanistic geckos are any gecko that is dark in color because they have more melanin. Black Nights are just a specific line that was originally highly selectively bred for a darker color, not unlike Black Pearls. Black Nights, just like any selectively bred line, can vary a lot in their appearance. This is especially true now as people have been breeding Black Nights that are not high in melanin just because of the price people are willing to pay for that label. Many purchasers don’t seem to understand that melanism in leos is selectively bred.

The percentages of ‘Black Night’ simply refer to the percentage of ancestry that can be attributed (according to the seller) to specifically ‘Black Night’ line geckos, it has nothing to do directly with how dark or high quality the gecko is. If you are looking to get into dark geckos, the label is not what matters (unless you are buying juveniles, that’s another discussion)- just buy the geckos that look the darkest. If you are attached to a label, then I’d get a Black Night x Black Pearl cross for the sake of outcrossing.

So a gecko that is 50% BN has one BN parent. A gecko that is 75% BN has 3 BN grandparents (so one of their parents is 50% BN). A gecko that is 87.5% BN and 12.5% Bold has 7 BN great-grandparents and 1 Bold grandparent. It does not actually refer at all to how dark or how bold the individual being described is.

‘Bold’ is even more subjective a label than ‘melanistic,’ so it doesn’t mean anything other than that the breeder/owner of the gecko in question thinks that their pattern is bold-looking.


Alright that clears it all up for me. Thank you so much!


Brilliant answer, thanks for the info.