Bog Turtle - Description

Description

The bog turtle is the smallest species of turtle in North America. The adults weigh approximately 110 grams (3.9 oz) when fully grown. It does not have a prominent snout. Its head is dark brown to black; however, it has a bright yellow, orange, or red spot on each side of its neck. The spot is often forked, facing posteriorly. The bog turtle has a dark skin color with an orange-red wash on the inside of the legs of some individuals. The carapace is domed and rectangular in shape, and it tends to be narrower toward the head and wider toward the tail. The carapace often has easily identifiable rings on the rough scales or scutes. The scutes may also have a radiating arrangement of lines. In some older individuals, and those that burrow frequently in coarse substrates, the shell may be smooth. Although generally black, a chestnut sunburst pattern in each scute is sometimes present on the carapace. The belly of the shell, the plastron, is also a dark brown to black color with light marks present.

The spotted turtle and painted turtle are similar in appearance to the bog turtle. The bog turtle is distinguishable from any other species of turtle by the distinctively colored blotch on its neck. A major difference between it and the spotted turtle is that the bog turtle has no coloration on the upper shell, unlike the latter species.

Mature male bog turtles have an average length of 9.4 centimeters (3.7 in) while the average female length is 8.9 centimeters (3.5 in) (straight carapace measurement). The males have a larger average body size than females, likely to facilitate males during male–male interactions during mate selection. The female has a wider and higher shell than the male, but the male's head is squared and larger than a female's of the same age. The plastron of the male looks slightly concave while the female's is flat. The male's tail is longer and thicker than the female's. The cloaca is further towards the end of the tail of the male bog turtle, while the female's cloaca is positioned inside the plastron. Juveniles are very difficult to sex.