What is the most definitive feature for confirming the Yellow Belly trait in ambiguous snakes?

The presence of distinct dark spots or smudging on the ventral scales

The presence of distinct dark spots, smudges, or stippling across the lighter belly scales is cited as the most definitive feature for confirming the Yellow Belly trait, especially when the pattern reduction on the dorsal or lateral areas might be ambiguous or subtle. A standard Ball Python typically possesses a belly that is creamy white or pale yellow and often nearly immaculate, featuring only faint, sparse dark smudging along the edges of the ventral scales, if any at all. In contrast, the Yellow Belly morph consistently alters this area by introducing scattered dark markings across the white or cream background, actively breaking up the uniformity. The degree of this spotting is variable, ranging from a few faint specks near the side-to-belly transition to heavy, almost confluent dark markings. Hobbyists are often advised to check the tail base transition zone specifically, as the spotting frequently becomes more concentrated and clearly defined there, providing a clear signature of the gene's expression.