Currently, pheromones and even hemi-penal shapes and sizes in some species are leading theories as to how or why different species of garters stick to their own kind. Recent cladistic studies (i.e. genetic relationship b/n T. elegans, ordinoides, and atratus in Northern California) however are suggesting exceptions and perhaps even possible reasons for why Thamnophis' genetic origins and lineages are such a headache in the first place. Reintegration is even theorized. Imagine evolving separately, and then some ol' dormant genes reawakens to allow you to breed back to that ancient family down the lane... "Why 'dem mutants is gonna change me spots!" Nature is always changing. Garter foods (esp. amphibians) change. I am of the mindset that some garter species may indeed be "re-inventing" themselves.

Just mad about garters!

Steven