The Western pond turtle (Clemmys marmorata) is the only turtle native to California. Found in wetland habitats, including rivers, streams and ponds, the pond turtle needs rocks, snags or other sites where it can bask.
The Western pond turtle has a relatively low-profile carapace (shell) compared to other turtles. It is olive-brown, dark gray or brown in color. There may (or may not) be faint line or spot patterns on the shell. Algae, other plants, snails, insects, fish, frogs (tadpoles and adults), and crustaceans such as crayfish form their diet. There is evidence that pond turtles will also eat carrion – dead mice and waterfowl, for example. They usually forage in the early morning and then again in the late afternoon.
Found along the West Coast from British Columbia to Baja, pond turtles in the southern part of the range are active all year while northern residents are usually active only from February to November.
These cold-blooded reptiles seldom leave the water except when they are basking. To maintain their body temperature around 90 to 95°, pond turtles will float in the water and bask intermittently.
The female needs well-drained silty soil near her home waterway to lay eggs. She will travel a mile or more along the shore or up to about 1,500 feet upland to make a shallow hole for her 1 to 13 white eggs. After covering the eggs with dirt her reproductive work is finished and she returns to the water. The eggs incubate for 80 to 126 days depending on the latitude. The sex of the offspring is determined by the temperature during development. At high temperatures, females develop while lower temperatures favor males. The temperature for sex determination is about 86° F. In northern areas the hatchlings remain in the nest over the winter, while in the southern part of their range they emerge in the fall.
Due to habitat destruction populations of Western pond turtles are declining. Northern California and Oregon now have the greatest numbers of these turtles.
Western pond turtles are most usually observed while basking. Being shy creatures, it is very difficult to approach them. Two turtles were basking on an old submerged bridge along the Tule River (Shasta County CA). One immediately fell into the water as evidenced by the “splash” in one picture. Thankfully the second Western pond turtle was slightly slower and I was able to get a portrait.