Giant Leopard Geckos
Giant makes a leopard gecko bigger: hatchlings come out longer and adults grow well past normal size. When you buy a Giant or a Super Giant, trust the pedigree over the scales, because an overfed normal is not the same animal as a genuine line.
About the Giant gene
Because Giant is a size trait and not a colour or pattern one, it sits on top of any morph a gecko already carries. The founding animal was a spontaneous 1999 hatchling of Ron Tremper's, and the largest lines within his bloodwork, prized for scale rather than markings, are among the more collectible ends of the hobby.
Appearance
You can tell a Giant is a Giant from the moment it hatches. Tremper's original animal measured 4.5 inches when it hatched instead of the usual 3, and it reached nearly 11 inches in ten months. Most adult Giants are over 10 inches, making them much longer than a normal leopard gecko. Super Giants are even larger. Moose reached 156 grams and was the founding Super Giant of the line. Breeders who work the largest lines in the Tremper bloodwork sell them as Godzilla Giants and Godzilla Super Giants.
Genetics
One copy of the Giant gene produces a Giant, while two copies result in the larger Super Giant, so the gene is incomplete dominant. Tremper called it co-dominance when he first wrote the gene up, and some in the hobby still do, but the wider record now uses incomplete dominant. A minority argue the gene behaves more like a line-bred size trait than clean dominance. There are no other names beyond Giant and Super Giant, and the gene has no allelic partners or known complex.
Known issues
Not all of the largest recorded Super Giants have lived for a long time. The Super Giant known as Moose, the founding Super Giant of the line, died unexpectedly in 2007 at six and a half years old. Other animals of record-weight have died within a couple of years of reaching their peak size. It is safer to buy or breed for size by judging a Giant by its length instead of pushing its weight through heavy feeding.