Genetically predisposed to become large in size. These giant-sized leopard geckos have two classes called Giant and Super Giant. Giant: Males reach 80-110 grams and females 60-90 grams by one year of age as typically seen in the heterozygous state. The largest Giants are called Super Giants: Males are over 110 grams and females over 90 grams by one year of age as typically seen in the homozygous condition. They can be any pattern or color. Unless both parents are known Super Giants there are no visible ways to tell a Giant from a Super Giant until 10-12 months of age.
In the summer of 1999, I hatched a huge baby from normal appearing parents - a purely spontaneous random event. This normal looking hatchling measured a staggering 4.5” in total length. This leopard grew to nearly 11” in total length by the age of 10 months and has not changed in size since.
As with any potential new mutation, care has to be made to test breed for several years to make sure that the morph breeds true. I selected five of my best looking female albinos and went about the task of making "hets". To my surprise and delight, the very first hatchling was an albino! This was a great bonus indeed, not only was the giant a male, but it was an albino het, as well, having come from the albino hets in the early phases of my albino project.
I then bred these albino and normal daughters back to their giant father, and since they were all females their size did not stand out to show that some of this first generation were indeed Giants themselves. When the resulting young hatched there were a number of them with long tails and elongated heads and bodies. One of these albinos turned into the now famous, “Moose”, which hatched in May 2001, making him the grandson of the original Giant mutation. Through test breeding it has been proven that Moose is a pure homozygous Super Giant albino. As of this writing, in November 2004, Moose weighs 156 grams, making him the heaviest leopard gecko ever known. He is 11 1/8 inches in total length, but his brother, who weighs less, is 11 3/8” long, making him the longest leopard I have ever measured.
For each new generation of Giants, I have selected the largest geckos to improve the line and therefore have been focusing on the Moose line of Giants. In 2002, after three generations of selective breeding, the first Giants were offered for sale to the public. Prices were somewhat higher for the Moose or Super Giant line. These efforts continue to this day by using Moose’s line; especially when introducing new color and patterns to the Giant project.
Findings show that when a Super Giant is bred to a normal-sized leopard the resulting heterozygous (Giant class) young tend to be intermediate in size between a normal and a Super Giant. The largest such hets possibly have some other genes contributing to their size. Super Giants can only be obtained with certainty by breeding Super Giant to Super Giant, but when the genes meet from two of the largest hets the probability is high of producing an unusually large homozygous or Super Giant, as well. This explains how Moose occurred. In my opinion, these genes behave as the first known case of co-dominance in leopard geckos.
Super Giant X Super Giant = 100% Super Giant
Super Giant X Giant = 50% Super Giant / 50% Giant
Super Giant X Normal = 100% Giant
Giant X Giant = 25% Super Giant, 50% Giant, 25% Normal
Giant X Normal = 50% Giant / 50% Normal