The differences between the redlegs and yellowlegs phenotypes of Glyptemys insculpta are suttle but distinctive. Present evidence suggests the yellowlegs phenotype resides in the western part of the biozone. The yellowlegs form may exist as peripheral isolates evolving eventually into a new subspecies if not disturbed by Homo sapiens. However, an alternative view may have the yellowlegs as ancestral stock. Harding (1999) mentions hybrids between Emydoidea blandingi and Glyptemys insculpta. The range of these two species overlaps with the greatest core concentration (as of 1985) remaining in the Great Lakes region. During the 1985 research, individuals of Emydoidea blandingi were present and studied with similarities noted with Glyptemys insculpta. The plastron of both species is very similar with the same arrangement of black spots on the plastral scutes. The skin color is yellowish on blandingii as is with the yellowlegs insculpta. It might be possible that a common emydid ancestor to both species resided in the same region and the ancestral color trait being yellow in regards to skin color. This would be a pre-Miocene event as the earliest known wood turtle (an adult male) found (Voorhies, 2000) was in the Hemphillian Miocene. If this is the case, the redlegs phenotype would be a derived apomorphic trait.
Ernest, Lovitch and Barborn in 1994 reported that in the cooler climes of the ice age, the wood turtle had a more southern distribution. The evidence suggested that the species could be found as far south as Tennessee and Georgia.
The noted differences in the phenotypes with dimensional measurements were the females with the Carastron values. Plastrons seem to be longer than the carapace with the yellowlegs phenotype. However, more measurements on more yellowlegs and redlegs individuals would be needed to draw an absolute conclusion.
In behavior, both phenotypes acted along similar lines and showed no differences in intelligence. This was true for the Tinklepaugh labyrinth experiment, the Yerkes space reaction experiment and the mirror reflection experiment.