Physical Characteristics:

     The western pond turtle averages a size of about 6-8 inches, with the largest turtles occurring in the northern part of its range.  It has a dark brown or olive colored shell (also called a carapace) with brown or black lines.  Head, neck, and limb coloration varies with location and age.  It is typically dark brown with a mottled yellow pattern.  Females have smaller heads, rounder carapaces, darker throats, and thinner tails than males.  Also, males have a concave plastron - the shell that covers the turtle's belly. 

Female and male western pond turtles (female on left, male on right)

Behavior:

     Because they are cold-blooded animals, western pond turtles spend much of their time thermoregulating.  This means that they use the heat of the sun to maintain their body temperature at an appropriate level.  They do this by laying on basking structures, such as emergent rocks and logs.  Western pond turtles thermoregulate out of water most frequently April through September.  Turtles may also thermoregulate underwater near the shore or in areas of emergent vegetation.

     Western pond turtles have excellent sight and hearing, and are very wary of approaching people.  They can sense a person from as far away as 100 meters or more.

     During the winter, western pond turtles are very inactive and enter a state of hibernation known as overwintering.  This overwintering period lasts from mid-October to March or April.

Diet:

     Western pond turtles primarily eat aquatic invertebrates, such as the larvae of beetles, dragonflies, stoneflies, and caddisflies.  They may also occasionally eat fish, frogs, and plants.  Western pond turtles spend a large amount of their time foraging for food and and most often forage at the bottom of water bodies.  Also, western pond turtles can only swallow their food underwater.

Aquatic Habitat Requirements:

     The western pond turtle utilizes ponds, streams, and rivers as aquatic habitat.  They prefer slow-moving water where basking structures and emergent vegetation are present.  Western pond turtles can tolerate water temperatures from 37 degrees F to 100 degrees F, but prefer water temperatures less than 95 degrees F.

Upland Habitat Requirements: 

     Western pond turtles require upland habitat for nesting, dispersal, and overwintering.  Nesting habitat generally consists of grassy areas with few shrubs or trees with soil that they can easily dig through.  On average, females will travel about 100 meters from their aquatic habitat to the nesting site.  The turtles excavate the nest by digging a flask-shapped hole in the soil which may take a few hours.

Reproduction:

     Female western pond turtles become sexually mature when they are 10-15 years old.  They breed in spring and nest between May and mid-July.  The clutch size can range from 2 to 13 eggs, with the average clutch size being 6 eggs.  The eggs hatch after 80-130 days of incubation, and the baby turtles are 1-1.2 inches in length.  Western pond turtles have been known to live for up to 70 years, but the average lifespan is around 40 years of age.

http://www.oregon.gov/OPRD/NATRES/NR_ElijahTurtle.shtml

Threats:

     Some of the western pond turtle's most common natural predators include: skunk, raccoon, osprey, gray fox, coyote, black bear, and mink.  In addition, the western pond turtle is threatened by invasive species, such as red-eared sliders, bullfrogs, and largemouth bass.  Red-eared sliders are invasive turtles that are not native to Oregon.  Sliders can outcompete western pond turtles for basking sites and food sources, and can also spread diseases which can be detrimental to pond turtle populations.  Western pond turtles can be easily distinguished from red-eared sliders by their coloration.  Red-eared sliders typically have yellow lines on their carapace, head, neck, and legs.  They also have a bright red ear patch on each side of their head.

Western Pond Turtle                                                                                 Red-eared Slider

                                                                                                                                          Virginia Department of Game and Inland Fisheries 

Works Cited:

Bettelheim, Matthew P. (2004): "The Western Pond Turtle, Clemmys marmorata... A Natural History of the Species."

Hays, David W., Kelly R. McAllister, Scott A. Richardson, and Derek W. Stinson (1999): "Washington State Recovery Plan of the Western Pond Turtle." Washington Department of Fish and Wildlife, Olympia, 66 pp.

Oregon Zoo website at: http://www.oregonzoo.org/Cards/Cascades/turtle.western.pond.htm