Text (Introduction)
The North American wood turtle belongs to the Family Emydidae. The Genus Clemmys (as of 1985) consisted of the wood turtle Clemmys insculpta, the bog turtle Clemmys muhlenbergi, the spotted turtle Clemmys guttata, and the Pacific pond turtle Clemmys marmorata. As of 2002, mitochrondrial DNA studies have now placed the wood and bog turtles in the Genus: Glyptemys and the pacific pond turtle in the Genus: Actinemys. Only the spotted turtle remains in the now monotypic Genus: Clemmys.
In 1985, several live Glyptemys insculpa were acquired for study. Individuals were selected from extreme ends of their natural range. Some individuals came from Wisconsin (Oneida county). This represented the western end of the range. Other individuals hailed from Northern Virginia. This represented the eastern as well as the southern part of their range. It immediately became apparent that there were consistent differences in coloration between the geographically separated groups. The eastern group consisted of the standard reddish orange color phase known in the vernacular as the "redlegs" (Pope, 1939). This standard morph also is characteristic of having a yellow-ringed iris. The western group of Glyptemys insculpta was different in that the skin color was yellow instead of reddish-orange and the iris was entirely black with no yellow ring. This phenotype will be referred to as the "yellowlegs" for the duration of this paper. Photographs of both phenotypes were taken and accompany this report. In the early twentieth century, Clifford Pope mentions having specimens of the yellowlegs phenotype which he describes as follows: " The soft parts lack the normal salmon red color of the adult, the plastron is dark except for a narrow light margin and a little light mottling ". Harding (1997) also mentions the color variation aspect and geographical distinctiveness of Glyptemys insculpta.
Measurements were recorded on eight selected individuals (4 males, 4 females- divided by 2 from each region). The data recorded was significant in regards to sexual dimorphism. Typically, male Glyptemys insculpta are noted for having wider heads, carapace's significantly longer than the plastron (always), longer claws, concave plastron, and thicker tails with the vent further out from the shell than the female. Female Glyptemys insculpta posses narrower heads, a carapace slightly longer than the plastron or in some cases, the plastron is longer than the carapace, shorter claws, flat plastron, and thinner tails with the vent close to the edge of the shell.
Tinklepaugh (1932) conducted experiments to determine the intelligence of Glyptemys insculpta. He concluded that this species had the learning capacity of a rat. The 1985 experiments of the same were done with a labyrinth constructed of 2 x 4's. The width of the corridors were ten inches wide with area covering twenty feet by twenty feet. In a variation of the original experiment, a three dimensional approach was conducted. Ramps were used to allow choices at three different levels. Incentives included food and females placed at specific locations.
Yerkes (1901) conducted the famous 'space' reaction experiments. Included on his guest list was Glyptemys insculpta. The experiment tested the animal's fear of heights. What was learned was the more aquatic the species, the more careless the species is in regards to heights. This behavior has evolved due to aquatic turtles being used to dropping off stones, logs, or whatever into buoyant water. The following test heights were chosen: two feet, five feet, ten feet, and twenty feet. In addition to Glyptemys insculpta, other species tested were the spotted turtle: Clemmys guttata, the redfoot tortoise: Geochelone carbonaria, and the Eastern box turtle, Terrapene carolina carolina.
The last series of experiments involved reaction to reflections in mirrors. The mirror used was twenty four inches wide. In addition to the North American wood turtle: Glyptemys insculpta, the following chelonian species were tested: the redfoot tortoise: Geochelone carbonaria, the yellowfoot tortoise: Geochelone denticulata, The Chaco tortoise: Geochelone chilensis, the Afghan tortoise: Testudo horsefieldi, the hingeback tortoise: Kinixys belliana, The Eastern gopher tortoise: Gopherus polyphemus, the Eastern box turtle: Terrapene carolina carolina, the Florida box turtle: Terrapene carolina bauri, and the Central American wood turtle: Rhinoclemmys pulcherima.
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