Western pond turtle (Actinemys marmorata), is designated as a “California Species of Special Concern” by the California Department of Fish and Game. This species is uncommon to common in all areas of suitable aquatic habitat throughout California, west of the Sierra-Cascade crest. It is absent only from most desert regions of California and elevations above 6,000 feet. Western pond turtle is the only abundant native turtle in California.
Western pond turtle is a small to medium-sized drab dark brown, olive-brown, or blackish turtle with a low carapace (upper shell). Shell length of adult pond turtles range from 3.5 to 8.5 inches and hatchlings are approximately one inch in length. The legs have prominent scales and are flecked and lined with black. The head usually has spots or a network of black, and may show some cream to yellowish coloring. Male pond turtles usually have a light throat with no markings, a low-domed carapace, and concave plastron (underside shell). Females usually have a lighter throat with dark markings, a high-domed carapace, and a flat or convex plastron, which is often more heavily patterned than the males’. The carapace of a young turtle is uniformly brown or olive above with yellow markings. The head, limbs, and tail are marked with dusky and pale yellow and the tail is almost as long as the shell.
Western pond turtle occurs in association with streams, rivers, and ponds containing suitable cover and basking sites. It can be associated with both permanent and ephemeral water sources, including perennial and intermittent streams. This species is active primarily during the day and is often seen basking above the water, but will quickly slide into the water if it feels threatened. Suitable basking sites along streams or ponds include partially submerged logs, rocks, mats of floating vegetation, or open streambanks. Suitable upland habitat, such as sandy banks or grassy fields, located adjacent to the aquatic habitat is required for egg-laying. Nesting may take place in a variety of soil types from loose sandy soils to compact soils, and in a variety of habitat types. Soil must be at least 4 inches deep for nesting. Eggs are laid from March to August, depending on local climate and water conditions, and incubation occurs for 73 to 80 days.
Western pond turtle is considered omnivorous and eats aquatic plant material, beetles, worms, aquatic invertebrates, crayfish, frog and salamander eggs, and occasionally small fish and frogs. Hatchlings and juveniles are preyed upon by a variety of vertebrate predators including, larger fish, bullfrogs, garter snakes, wading birds, and some mammals.
Pond turtles occur a many of the WHF preserves that provide suitable habitat.