"armpit" holes?

[rhino43grr]

my fiancee asked me why leopard geckos look like they have holes in their "armpits" and i really didn't have an answer for her, does anybody know?

 

[Stitch]

They are more like indentations, not holes. You may notice that once your gecko gets nice and plumpy this area will swell. Here's a link to describe them better: Fat armpits