CaliforniaHerps.com

A Guide to the Amphibians
and Reptiles of California


Northern Western Pond Turtle - Actinemys marmorata

(Baird and Girard, 1852)


(= Western Pond Turtle or Pacific Pond Turtle - Actinemys marmorata)
Click on a picture for a larger view



Pacific Pond Turtle Range MapRange in California: Red and Purple


observation link





Adults
Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle
Adult female, Butte County
© Jackson Shedd
Adult, Santa Clara County © Neil Keung Adult male, Kings County
© Patrick Briggs
Adult, Alameda County
Pacific Pond Turtles Pacific Pond Turtles Pacific Pond Turtles Pacific Pond Turtle
Adults and juveniles, Alameda County
Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle
  Adult female, Mendocino County   Adult female, crossing a trail in late May, San Mateo County.
Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle
Adult female, Contra Costa County Adult, Mendocino county
Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle
Adult, Napa County (showing inguinals on right) © James R. Buskirk Basking adult male (left) and female (right), San Mateo County. Adult, Del Norte County. © Alan Barron
Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle
Adults, Santa Clara County © Neil Keung Adult, Colusa County © Kinji Hayashi Adult, Napa County © James R. Buskirk Adults, Modoc County
© James R. Buskirk
Pacific Pond Turtles Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle
Basking adults, Shasta County
© James R. Buskirk
Adult, Fresno County © James R. Buskirk Adults showing their climbing ability, Alameda County © Mark Gary Basking adult female, San Mateo County
Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle
Adult male, San Mateo County Basking adult, San Mateo County Adult female, Solano County
© Adam Clause.
Animal captured and handled under state Scientific Collecting Permit and released at point of capture.
Kings County © Brian Hubbs
Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle
Adult, Contra Costa County Adult, Alameda County Adult male in a Madera County mountain creek © Brian Hubbs
Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle
  Adult female, Fresno County © Patrick Briggs  
Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle  
Adult, El DoradoCounty
© Brandon Huntsberger
Adult, Sacramento County (with smaller Red-eared Slider)
© Brandon Huntsberger
Adult, Kings County © Patrick Briggs  
Pacific Pond Turtle
A lot of pond turtles in Marin County © Brian Hubbs
Pacific Pond Turtle
A lot of pond turtles in Alameda County © Mark Gary
 
Piebald Males From the San Joaquin Valley
"Large old males from San Joaquin Valley, Calif. may be marked with large areas of beige and pinkish beige." (Stebbins, 2003)

Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle
Adult male, Fresno County © Patrick Briggs Adult male, Kings County, (showing piebald melanism which is characteristic of males in the San Juaquin Valley.)
© Patrick Briggs
Pacific Pond Turtle      
Piebald adult males, Fresno County
© Brian Hubbs
     
       
Some Male / Female Differences
Pacific Pond Turtles Pacific Pond Turtle Pacific Pond Turtle  
Plastron of adult male (left)
Plastron of adult female (right)
© Pierre Fidenci
Male, Santa Clara County, showing the raised areas towards the rear of the head indicative of the male sex.
© Brian Hubbs
Males usually have a light throat with no markings. Females usually have a throat with dark markings
Male (left) Female (right) for comparison, Lake County © Brian Hubbs
 
 
Juveniles
Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle
Hatchling, Mendocino county Hatchling, Fresno County © Patrick Briggs
Pacific Pond Turtle      
Juvenile, Siskiyou County
© Kinji Hayashi
     
       
Pond Turtle Tracking
Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle
Santa Clara County turtles with transmitters attached to their shells. An antenna with a radio receiver that can find these transmitters is used to find the turtles and track their movement in order to study their behavior. Transmitters on females like the one on the far left are placed on the side of the shell to prevent obstacles to males during breeding. The transmitters are removed without damaging the shells when research is completed. © Neil Keung  
Animal capture and handling authorized under Federal permits, State Parks permits, and Open Space Authority permits.
Pacific Pond Turtle Pacific Pond Turtle Pacific Pond Turtle  
This Santa Clara County turtle travelled away from a dry creek in summer to bury itself in an upland location above the creek in oak woodland habitat where it will stay until the following Spring. The turtle was found by tracking the transmitter which you can see attached to its shell. © Neil Keung 
Animal capture and handling authorized under Federal permits, State Parks permits, and Open Space Authority permits.
Adult in a shallow creek in Santa Clara County, showing how well-camouflaged these turtles are. © Neil Keung
Adult, Santa Clara County, camouflaged on the bottom. Try to find it.
© Neil Keung
 
       
Comparison With Normal Red-eared Sliders - Trachemys scripta elegans
Red-eared Slider Red-eared Slider Pacific Pond Turtle head and neck Red-eared Slider
Two adult Red-eared Sliders (left) compared with a much smaller adult Pacific Pond Turtle (right).
© Jeff Ahrens.
Animal capture and handling authorized under SCP or specific authorization from CDFW.
Ventral view of four adult Red-eared Sliders, with a much smaller adult Pacific Pond Turtle in the middle.
© Jeff Ahrens.
Animal capture and handling authorized under SCP or specific authorization from CDFW.
The head and neck of the Pacific Pond Turtle is mottled, with no red stripe behind the eye. There is usually a prominent red stripe behind the eye of the Red-eared Slider.
       
Red-eared Slider    
A useful way to differentiate Pacific Pond Turtles from Red-eared Sliders, according to wildlife biologist Brandon Stidum, "...is to look at the marginal scutes 8-12 (...the scutes above the tail, or back scutes). Sliders have bifid or slightly forked scutes, where Western Pond Turtles do not; theirs are all smooth and do not split (except for traumatic injuries, but it’s usually only one or a few, not all scutes). The forking in the tail gives red-eared sliders the appearance that the tail is serrated or split in appearance.  While looking for the presence and size of inguinal and axillary scutes is the best way to differentiate between the 2 once you have them in hand, a good way to do it from a distance is to look at the back scutes of the turtles."     
     
Identification Confusion with Melanistic Red-eared Sliders
red-eared slider red-eared slider red-eared slider
Melanistic adult Red-eared slider - Trachemys scripta elegans, Riverside County. © Bob Parkard

Introduced melanistic sliders and old sliders whose red "ears" have faded, are often difficult to distinguish from the California native Pacific Pond Turtle, especially at a distance in the field, and even in hand. According to Bob Packard, with the Western Riverside County MSHCP Biological Monitoring Program, his organization confirms the identification of these turtles based on the presence of large inguinal and axillary scutes on the sliders, which are absent on the pond turtles, and by an interesting behavioral clue: the majority of sliders tend to be aggressive, biting readily, while pond turtles are far more reluctant to bite.

You can also use the information illustrated above about differentiating the two species from a distance by observing the rear marginal scutes, or back scutes, (scutes above the tail).

More pictures of melanistic sliders can be seen on the Red-eared Slider page.

red-eared slider

Melanistic adult Red-eared slider - Trachemys scripta elegans, (without red on the head) Riverside County.
© Bob Parkard
   
Eggs
Pacific Pond Turtle eggs pond turtle life cycle    
A. marmorata Eggs, © Patrick Briggs Western Pond Turtle Life Cycle:
Adult, Juvenile, and Egg, Butte County.
© The Chico Turtle Lab
   
       
Habitat
Pacific Pond Turtle Habitat Pacific Pond Turtle Habitat Pacific Pond Turtle Habitat Pacific Pond Turtle Habitat
Habitat, river, Mendocino County Habitat, large pond, Marin County Habitat, forest creek, Mendocino County Habitat with turtle, San Joaquin County
© James R. Buskirk
Pacific Pond Turtle Habitat Pacific Pond Turtle Habitat Pacific Pond Turtle Habitat Pacific Pond Turtle Habitat
Habitat, large lake, Sacramento County Habitat, small creek, Santa Clara County Habitat, Contra Costa County Habitat, Napa County
© James R. Buskirk
Pacific Pond Turtle Habitat Pacific Pond Turtle Habitat Pacific Pond Turtle Habitat Pacific Pond Turtle Habitat
Habitat, a small pond in the hills of Alameda County Habitat, San Mateo County Habitat, meadow in Siskiyou County
© Kinji Hayashi
Pacific Pond Turtle Habitat Pacific Pond Turtle Habitat Pacific Pond Turtle Habitat Pacific Pond Turtle Habitat
Habitat, San Mateo County Habitat, Tulare County © Patrick Briggs

Adult basking on branches in pond, Contra Costa County.
Where no objects are available in the water for basking, pond turtles will use branches overhanging the water, or they will bask on the shore.

Habitat, Alameda County © Mark Gary
Pacific Pond Turtle Habitat x    
Habitat, Alameda County San Mateo County Park Sign
   
       
Short Videos
Pacific Pond Turtles Pacific Pond Turtle Pacific Pond Turtles  
Northern Western Pond Turtles compete for limited basking space on a small pond. Northern Western Pond Turtles turtles basking in the sun. Northern Western Pond Turtles turtles in an Alameda County pond.  
     
Description
 
Size
3.5 - 8.5 inches in shell length (8.9 - 21.6 cm). (Stebbins 2003)
Hatchlings are aproximately 1 inch (2.5 cm) in shell length.
The tail of a young turtle is almost as long as its shell.

Appearance
A small to medium-sized drab dark brown, olive brown, or blackish turtle with a low unkeeled carapace.
Color and Pattern
Usually with a pattern of lines or spots radiating from the centers of the scutes.
The plastron lacks hinges, and has 6 pairs of shelds which can be cream or yellowish in color with large dark brown markings, or unmarked.
The legs have black speckling and may show cream to yellowish coloring.
The head usually has a black network or spots may show cream to yellowish coloring.
Turtles south of the Transverse Ranges tend to be lighter, from yellowish brown to light brown.
Male / Female Differences
Males usually have a light throat with no markings, a low-domed carapace (a flatter shell), and a concave plastron.
Females usually have a throat with dark markings, a high-domed carapace (a taller shell), and a flat or convex plastron which tends to be more heavily patterned than the male's.

Life History and Behavior

Activity
Diurnal and aquatic.
This turtle is often seen basking above the water, but will quickly slide into the water when it feels threatened.
Seldom basks by floating at the surface. Active from around February to November.
May be active during warm periods in winter.
P ond turtles hibernate underwater during several months in the winter. They cluster in the shallow end of the pond.
A pond turtle will estivate during summer droughts by burying itself in soft bottom mud. When creeks and ponds dry up in summer, some turtles that inhabit creeks will travel along the creek until they find an isolated deep pool, others stay within moist mats of algae in shallow pools while many turtles move to woodlands above the creek or pond and bury themselves in loose soil where they will overwinter until temperatures warm up enough for them to become active and the heavy winter flows of the creek subside, and then they return to the creek in Spring.

Don't Pick up a Turtle Just Because You Find it Walking On Land!
Pond turtles sometimes leave the water to search for food, more water, or to lay their eggs in the spring - typically April and May, and can travel as far as a hundred yards. If you see a pond turtle walking on the land, it is most likely not sick, so you should leave it alone. Many concerned people who think they are helping a turtle by picking it up and bringing it to a wildlife rehabilitation center are actually harming it by removing it from the wild unnecessarily.
Territoriality
When seeking or protecting a basking spot, turtles may show aggressive behavior by opening the mouth and exposing the yellow and pinkish mouth lining to scare off another turtle. Occasionally they will also bite or ram.
Diet and Feeding
Eats aquatic plants, invertebrates, worms, frog and salamander eggs and larvae, crayfish, carrion, and occasionally frogs and fish.
Breeding
Mating occurs in April and May.
Adults do not mate until they are aproximately eight to ten years old.
Sometime between April and August, females climb onto land to dig a nest, usually along stream or pond margins, where they lay a clutch of 2 - 11 eggs.
Some females lay two clutches in a year while others lay eggs every other year.
Females in the Bay Area were found to prefer to lay their eggs in sunny areas with grass about a foot and a half high covering about 85 percent of the ground. (Carolyn Jones, SFGate.com, 7/31/13)

Geographical Range

All populations in California  "... north of the San Francisco Bay area plus populations from the Great Central Valley north including the apparently introduced Nevada population..." are the Northern Western Pond Turtle, according to the authors. ** 
(The Southern Western Pond Turtle "... is restricted to those populations inhabiting the central coast range south of the San Francisco Bay area to the species’ southern range boundary, including the Mojave River ... Although we tentatively include populations from Baja California in E. pallida, we also recognize that these animals may represent a distinct species pending results from additional analyses." **)

It is not clear what species of pond turtle occurs immediately south, east, and west of the San Francisco Bay since no specimens from that area were used in the study which described the two species. There is no mention of hybrids occurring in this area. ("Emys marmorata and E. pallida show very limited intergradation in a few populations in the northern central coast range and adjacent Sierra Nevada foothills, although at all intergrade sites we also found pure individuals of the locally prevalent species.") Based on the range description of A. pallida cited above, I have shown a zone south, west, and east of the S.F. Bay on my range map where the pond turtle species is not known but which I will group with A. marmorata until I learn otherwise. There is another zone in the southern Tehachapi Mountains which is also not represented by samples in the recent study, so the contact area between the two species there is also not known, but which I will also group with A. marmorata for now.

A. marmorata ranges north of California into Oregon, Washington and British Columbia (west of the crest of the Cascades and Sierras) (It may now be extinct in western Washington and British Columbia.) An isolated population occurs at Susanville. Another isolated population occurs in Nevada in the Truckee, Carson, and East Walker Rivers (Stebbins 2003).

Full Species Range Map
Elevational Range
Stebbins (2003) describes the elevation range of the Western Pond Turtle - Clemmys marmorata, which has now been split into two species, as "Sea level to around 6,696 ft. (2,041 m) but mostly below 4,980 ft. (1,371 m)."

Habitat
Found in ponds, lakes, rivers, streams, creeks, marshes, and irrigation ditches, with abundant vegetation, and either rocky or muddy bottoms, in woodland, forest, and grassland. In streams, prefers pools to shallower areas. Logs, rocks, cattail mats, and exposed banks are required for basking. May enter brackish water and even seawater.

Notes on Taxonomy
The Western Pond Turtle, Actinemys marmorata, has been split into two species, following the previous split of the species into two subspecies,
A. m. marmorata
and A. m. pallida.

The authors "...propose using the name Emys marmorata for all populations north of the San Francisco Bay area plus populations from the Great Central Valley north.... Emys pallida is restricted to those populations inhabiting the central coast range south of the San Francisco Bay area to the species’ southern range boundary, including the Mojave River." *

* Phillip Q. Spinks, Robert C. Thomson, and H. Bradley Shaffer.
The advantages of going large: genome wide SNPs clarify the complex population history and systematics of the threatened western pond turtle.
Molecular Ecology. 23(9): 2228-2241. June, 2014.

--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Janzen, Hoover, and Shaffer (1997 Chelonian Conservation Biology 2(4): 623-626) concluded that southern populations of A. marmorata, found in Baja California and adjacent southern California, are a different species from those to the north.

Spinks and Shaffer argued that subspecies should be abandoned because they are not supported on molecular grounds. (Spinks and Shaffer - 2005 Mol. Ecol. 14:2047-2064)

In 2010 Spinks (Spinks et al., 2010, Mol. Ecol. 19: 542-556) demonstrated deep phylogeographic divergence within the species, potentially warranting species recognition.


Alternate and Previous Names (Synonyms)

Actinemys marmorata marmorata - Northwestern Pond Turtle (Stebbins & McGinnis 2012)
Clemmys marmorata marmorata - Northwestern Pond Turtle (Stebbins 1966, 1985, 2003)
Clemmys marmorata - Pacific Pond Turtle (Stebbins 1954)

Conservation Issues  (Conservation Status)

Northern Western Pond Turtles may be nearly extinct in western Washington and British Columbia.


The Western Pond Turtle is in decline throughout 75 - 80% of its range. (Stebbins, 2003.) There a number of reasons for this decline.

Beginning in the 19th century, the commercial harvesting of Western Pond Turtles for food was a major threat to the species. That trade continued at least into the 1930s: Nussbaum, Brodie & Storm, 1983, remark that in the 1930s, Western Pond Turtles were trapped for food in California and sold to markets in San Francisco.

Another cause for the decline of the species was the massive wetland drainage projects in the Great Valley of the early 20th century which destroyed numerous wetlands and lakes and altered rivers, all of which destroyed or reduced suitable habitat for the Western Pond Turtle. Tulare lake, now gone, was once the home to an estimated 3.5 million pond turtles, almost all of which are now extinct in the area. (Stebbins & McGinnis, 2012.) The destruction or degredation of other wetlands throughout the state has certainly also added to the decline.

The introduction of non-native turtles into Western Pond Turtle habitat, especially the two most successful invasive turtle species, the Red-eared Slider and the Painted Turtle, has been another cause of the decline of the Western Pond Turtle. Both species are common in the pet trade and feral turtles now found in California were most likely released by their owners. Since the Western Pond Turtle is the only native freshwater turtle in its historic range, it did not develop the ability to successfully compete for resources with other species of turtles, and both the Red-eared Slider and the Painted Turtle produce nearly twice as many offspring as the pond turtle which allows them to overwhelm and out-compete the pond turtle population.

Another threat to the pond turtle has been the American Bullfrog, an invasive species that has spread throughout the state. In 1994 report, Dan C. Holland writes that the invasive bullfrog (Rana catesbeiana) is a known predator of Western Pond Turtles, and the report includes a picture of a bullfrog preying on a juvenile pond turtle in San Diego County. Bullfrogs breed in such large numbers that adults can eventually eat so many hatchling turtles that fewturtles can survive to adulthood and after the existing adults die off there will be no more turtles at that location.  (Holland, Dan C. The Western Pond Turtle: Habitat and History. Final Report. Prepared for: U. S. Department of Engergy Bonneville Power Administration Environment, Fish and Wildlife... Portland OR.1994)

Photographic evidence also exists that shows that bullfrogs eat hatchling painted turtles.

Taxonomy
Family Emydidae Box and Basking Turtles Gray, 1825
Genus Actinemys Western Pond Turtles Agassiz, 1857
Species

marmorata Northern Western Pond Turtle (Baird and Girard, 1852)
Original Description
Clemmys marmorata - (Baird and Girard, 1852) - Proc. Acad. Nat. Sci. Philadelphia, Vol. 6, p. 177

from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz

Meaning of the Scientific Name
Actinemys - actin - ray or beam, and -emys - turtle
marmorata
- Latin - marbled - refers to the marbled carapacial pattern

from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz

Related or Similar California Turtles
Actinemys pallida - Southern Western Pond Turtle

C. p. bellii - Western Painted Turtle

T. s. elegans - Red-eared Slider

More Information and References (Referring to A. marmorata and A. pallida)
California Department of Fish and Wildlife

SDNHM

James R. Buskirk has generously provided age and gender identification for many of the turtles shown here.

Stebbins, Robert C., and McGinnis, Samuel M.  Field Guide to Amphibians and Reptiles of California: Revised Edition (California Natural History Guides) University of California Press, 2012.

Stebbins, Robert C. California Amphibians and Reptiles. The University of California Press, 1972.

*Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin Company, 2003.

Behler, John L., and F. Wayne King. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, 1992.

Powell, Robert., Joseph T. Collins, and Errol D. Hooper Jr. A Key to Amphibians and Reptiles of the Continental United States and Canada. The University Press of Kansas, 1998.

Bartlett, R. D. & Patricia P. Bartlett. Guide and Reference to the Turtles and Lizards of Western North America (North of Mexico) and Hawaii. University Press of Florida, 2009.

Carr, Archie. Handbook of Turtles: The Turtles of the United States, Canada, and Baja California. Cornell University Press, 1969.

Ernst, Carl H., Roger W. Barbour, & Jeffrey E. Lovich. Turtles of the United States and Canada. Smithsonian Institution 1994. (2nd Edition published 2009)

St. John, Alan D. Reptiles of the Northwest: Alaska to California; Rockies to the Coast. Lone Pine Publishing, 2002.

Lemm, Jeffrey. Field Guide to Amphibians and Reptiles of the San Diego Region (California Natural History Guides). University of California Press, 2006.

Watch more short movies of this turtle at Endangered Species International (www.endangeredspeciesinternational.org)

Conservation Status

The following status listings come from the Special Animals List and the Endangered and Threatened Animals List which are published by the California Department of Fish and Wildlife.


The Special Animals List shows this turtle as Emys marmorata - Western Pond Turtle. It does not recognize the 2014 description of two species of pond turtles.

Special Animals List Notes:

1) The paper: Spinks, Phillip Q. & H. Bradley Shaffer. 2005. Range-wide molecular analysis of the western pond turtle (Emys marmorata): cryptic variation, isolation by distance, and their conservation implications. Molecular Ecology (2005) 14, 2047-2064. determined that the current subspecies split was not warranted. Therefore, we are now tracking the western pond turtle only at the full species level.

2) The paper: Spinks, Phillip Q., & H. Bradley Shaffer. 2009. Conflicting Mitochondrial and Nuclear Phylogenies for the Widely Disjunct Emys (Testudines: Emydidae) Species Complex, and What They Tell Us about Biogeography and Hybridization. Systematic Biology. 58(1): pp. 1-20 determined that the correct genus name is Emys.


Organization
Status Listing
NatureServe Global Ranking G3G4 Vulnerable - Apparently Secure
NatureServe State Ranking S3

Vulnerable in the state due to a restricted range, relatively few populations (often 80 or fewer), recent and widespread declines, or other factors making it vulnerable to extirpation from the state.

U.S. Endangered Species Act (ESA) None
California Endangered Species Act (CESA) None
California Department of Fish and Wildlife SSC Species of Special Concern
Bureau of Land Management S Sensitive
USDA Forest Service S Sensitive
IUCN VU Vulnerable


 

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