Animal Diversity Web

Ge­o­graphic Range

West­ern pond tur­tles (also known as Pa­cific pond tur­tles and Pa­cific mud tur­tles) are na­tive to the west coast and are found from Baja Cal­i­for­nia, Mex­ico north through Klick­i­tat County, Wash­ing­ton. Within this re­gion, there are two sub­species: north­west­ern pond tur­tles (E. m. mar­morata) are found in areas north of the Amer­i­can River in Cal­i­for­nia; south­west­ern pond tur­tles (E. m. pal­l­ida) are found in areas south of San Fran­cisco. There are iso­lated in­land pop­u­la­tions in Wash­ing­ton, Ore­gon, Cal­i­for­nia, Nevada and Idaho. It has been sug­gested that some of these iso­lated pop­u­la­tions rep­re­sent in­tro­duc­tions through human trans­port, al­though there is no clear ev­i­dence for this. ("WEST­ERN POND TUR­TLE (Clem­mys mar­morata). Nat­ural His­tory.", 1997; "West­ern Pond Tur­tle: Clem­mys mar­morata", 1999; Bet­tel­heim, 2006; "West­ern Pond Tur­tle (Clem­mys Mar­morata)", 2004)

• Biogeographic Regions
• nearctic
  • native

Habi­tat

West­ern pond tur­tles use both aquatic and ter­res­trial habi­tats. They are found in rivers, lakes, streams, ponds, wet­lands, ver­nal pools, ephemeral creeks, reser­voirs, agri­cul­tural ditches, es­tu­ar­ies, and brack­ish wa­ters. West­ern pond tur­tles pre­fer areas that pro­vide cover from preda­tors, such as veg­e­ta­tion and algae, as well as bask­ing sites for ther­moreg­u­la­tion. Such cover also pro­vides shel­ter when win­ter­ing. West­ern pond tur­tles are ob­served in aquatic habi­tats rang­ing from 1 to 40 de­grees Cel­sius. Ju­ve­niles are found pri­mar­ily in areas be­tween 12 and 33 de­grees Cel­sius, whereas adults are found be­tween 10 and 17 de­grees Cel­sius. Adults tend to favor deeper, slow mov­ing water, whereas hatch­lings search for slow and shal­low water that is slightly warmer. Ter­res­trial habi­tats are used for win­ter­ing and con­sist usu­ally of bur­rows in leaves and soil. West­ern pond tur­tles also lay their eggs in ter­res­trial habitats.​They are rarely found at al­ti­tudes above 1500m. ("West­ern Pond Tur­tle (Clem­mys Mar­morata)", 2005; "WEST­ERN POND TUR­TLE (Clem­mys mar­morata). Nat­ural His­tory.", 1997; "West­ern Pond Tur­tle: Clem­mys mar­morata", 1999; Bet­tel­heim, 2006; Gray, 1995; "West­ern Pond Tur­tle (Clem­mys Mar­morata)", 2004; Reese and Welsh, 1997; Reese and Welsh, 1998)

• Habitat Regions
• temperate
• terrestrial
• freshwater

• Aquatic Biomes
• lakes and ponds
• rivers and streams
• brackish water

• Wetlands
• marsh
• swamp

• Other Habitat Features
• suburban
• agricultural
• riparian
• estuarine

• Range elevation

  0 to 1980 m

  0.00 to 6496.06 ft

• Range depth

  1 to 5 m

  3.28 to 16.40 ft

Phys­i­cal De­scrip­tion

West­ern pond tur­tles are gen­er­ally yel­low­ish with dark blotches in the cen­ter of the plas­tron. There is mar­bled pat­tern­ing through­out the body. The dor­sal area is gen­er­ally dark brown to olive. The shell tends to be low, wide, and smooth. Adult males have a larger head, pointier snout, thicker tail base, and a wider neck char­ac­ter­ized by white and yel­low on the chin and throat. Adult fe­males tend to have a blunt snout, thin­ner tail base, and darker mark­ings on the chin and throat. West­ern pond tur­tles have webbed feet. Hatch­lings tend to have a longer tail, soft shell, and be a lighter brown; dark­en­ing as they age. They weigh ap­prox­i­mately 5g at hatch­ing and mea­sure around 28 mm in shell length. The south­ern sub­species tends to grown only to 115 mm in shell length, north­ern sub­species reach 210 mm in shell length. ("Ex­po­sure Fac­tors for West­ern Pond Tur­tle (Clem­mys mar­morata)", 1999; "WEST­ERN POND TUR­TLE (Clem­mys mar­morata). Nat­ural His­tory.", 1997; Bet­tel­heim, 2006; Gray, 1995; "West­ern Pond Tur­tle (Clem­mys Mar­morata)", 2004)

• Other Physical Features
• ectothermic
• heterothermic
• bilateral symmetry

• Sexual Dimorphism
• female larger
• sexes colored or patterned differently
• sexes shaped differently

• Range mass

  623.7 to 935.55 g

  21.98 to 32.97 oz

• Range length

  110 to 210 mm

  4.33 to 8.27 in

• Average basal metabolic rate

  Unknown cm3.O2/g/hr

De­vel­op­ment

Fe­males de­posit eggs in a nest they dig on land at night. After in­cu­ba­tion, hatch­lings leave the egg only if the tem­per­a­ture is below 81 de­grees Fahren­heit. Hatch­lings tends to be male if the in­cu­ba­tion tem­per­a­ture was below 86 de­grees Fahren­heit or fe­male if the in­cu­ba­tion tem­per­a­ture was above 86 de­grees Fahren­heit). Hatch­lings im­me­di­ately re­turn to the water and grow at a rate of 3.29 mm/month, .08 mm/month, .05 mm/month, and .04 mm/month dur­ing suc­ces­sive growth sea­sons. Growth is ac­com­pa­nied by dark­en­ing of the body and hard­en­ing of the shell. After about 8 years of growth, the rate slows as the tur­tles ma­ture into adults. Growth rate de­pends on en­vi­ron­men­tal fac­tors such as water, tem­per­a­ture, and food abun­dance. Colder water and less food slows growth. ("WEST­ERN POND TUR­TLE (Clem­mys mar­morata). Nat­ural His­tory.", 1997; "West­ern Pond Tur­tle: Clem­mys mar­morata", 1999)

• Development - Life Cycle
• temperature sex determination

Re­pro­duc­tion

West­ern pond tur­tle males court fe­males using their fore­limbs to scratch the an­te­rior edge the fe­male’s cara­pace. This is fol­lowed by the fe­male rais­ing her pos­te­rior end, after which mat­ing oc­curs. Due to the seclu­sive na­ture of these an­i­mals there is not much known about the mat­ing process. ("WEST­ERN POND TUR­TLE (Clem­mys mar­morata). Nat­ural His­tory.", 1997; "West­ern Pond Tur­tle: Clem­mys mar­morata", 1999)

• Mating System
• polygynandrous (promiscuous)

West­ern pond tur­tles mate from May through Au­gust, with most fe­males lay­ing eggs in al­ter­nat­ing years. Al­though the av­er­age age of ma­tu­rity is be­tween 8 and 14 years of age, fe­males in the south­ern sub­species oc­ca­sion­ally reach ma­tu­rity at an ear­lier age. Nests are built up to 402 m from the water with an av­er­age dis­tance of 28 m and re­quire at least 10 cm of soil. Hatch­ing suc­cess rates are ap­prox­i­mately 70%, as there is a high rate of nest pre­da­tion and com­plete nest fail­ure. Nests are gen­er­ally found in flat areas with low veg­e­ta­tion and dry, hard soil. In­cu­ba­tion takes ap­prox­i­mately 3 months, with most hatch­lings stay­ing in the nest cham­ber until the fol­low­ing spring. Some hatch­lings in south­ern and cen­tral Cal­i­for­nia emerge in the fall. ("Ex­po­sure Fac­tors for West­ern Pond Tur­tle (Clem­mys mar­morata)", 1999; "West­ern Pond Tur­tle (Clem­mys Mar­morata)", 2005; "WEST­ERN POND TUR­TLE (Clem­mys mar­morata). Nat­ural His­tory.", 1997; Gray, 1995; "West­ern Pond Tur­tle (Clem­mys Mar­morata)", 2004)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• oviparous

• Breeding interval

  Western pond turtle females breed in alternating years.

• Breeding season

  The breeding season takes place from May through August.

• Range number of offspring

  1 to 13

• Average number of offspring

  6

• Range gestation period

  80 to 100 days

• Range age at sexual or reproductive maturity (female)

  8 to 14 years

• Range age at sexual or reproductive maturity (male)

  8 to 14 years

After the eggs are laid, there is no ev­i­dence of parental care. ("West­ern Pond Tur­tle (Clem­mys Mar­morata)", 2005; "WEST­ERN POND TUR­TLE (Clem­mys mar­morata). Nat­ural His­tory.", 1997; "West­ern Pond Tur­tle: Clem­mys mar­morata", 1999)

• Parental Investment
• no parental involvement
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female

Lifes­pan/Longevity

As hatch­lings, west­ern pond tur­tles are easy prey and have a sur­vival rate of 8 to 12%. Adults can live 40 to 70 years or even longer. As adults the av­er­age sur­vival rate in­creases to around 45%. In adults there is a 4:1 male to fe­male ratio, which is prob­a­bly a re­flec­tion of the pro­longed amount of time fe­males are ex­posed to ter­res­trial preda­tors while lay­ing eggs. ("WEST­ERN POND TUR­TLE (Clem­mys mar­morata). Nat­ural His­tory.", 1997; "West­ern Pond Tur­tle: Clem­mys mar­morata", 1999; Gray, 1995)

• Range lifespan
  Status: wild

  80 (high) years

• Typical lifespan
  Status: wild

  40 to 70 years

• Average lifespan
  Status: wild

  50 years

Be­hav­ior

West­ern pond tur­tles are not gen­er­ally ter­ri­to­r­ial al­though ag­gres­sive en­coun­ters in­clud­ing ram­ming, bit­ing, and threat­en­ing with open-mouth ges­tures are com­mon over bask­ing areas. They tend to hunt late in the day and bask in­ter­mit­tently in order to main­tain an av­er­age body tem­per­a­ture of 28 de­grees Cel­sius. The max­i­mum body tem­per­a­ture is 40 de­grees Cel­sius, al­though they usu­ally avoid going over 34 de­grees Cel­sius. This species is most ac­tive in water that reaches 15 de­grees Cel­sius. Al­though pri­mar­ily as­so­ci­ated with an aquatic en­vi­ron­ment, these tur­tles also spend sig­nif­i­cant amounts of time in ter­res­trial habits, pri­mar­ily dur­ing over­win­ter­ing and mov­ing be­tween aquatic areas. They move be­tween over­win­ter­ing sites as well, usu­ally 4 times. ("West­ern Pond Tur­tle (Clem­mys Mar­morata)", 2005; "WEST­ERN POND TUR­TLE (Clem­mys mar­morata). Nat­ural His­tory.", 1997; "West­ern Pond Tur­tle: Clem­mys mar­morata", 1999; Reese and Welsh, 1997)

• Key Behaviors
• terricolous
• natatorial
• diurnal
• motile
• sedentary
• hibernation
• solitary

• Range territory size

  2833 to 10117 m^2

Home Range

Male west­ern pond tur­tle home ranges av­er­age 1 hectare, or around 200 to 5623 square me­ters. Fe­male home ranges av­er­age only 0.3 hectares or up to 2100 square me­ters. Ju­ve­niles have home ranges up to 3175 square me­ters or around 0.4 hectares. ("Ex­po­sure Fac­tors for West­ern Pond Tur­tle (Clem­mys mar­morata)", 1999; "West­ern Pond Tur­tle (Clem­mys Mar­morata)", 2005; "West­ern Pond Tur­tle: Clem­mys mar­morata", 1999)

Com­mu­ni­ca­tion and Per­cep­tion

West­ern pond tur­tles find food using both sight and smell. More­over, based on the mat­ing rit­ual it is clear that touch is im­por­tant in com­mu­ni­ca­tion among sexes. ("WEST­ERN POND TUR­TLE (Clem­mys mar­morata). Nat­ural His­tory.", 1997; Bet­tel­heim, 2006)

• Communication Channels
• tactile

• Perception Channels
• visual
• tactile
• chemical

Food Habits

West­ern pond tur­tles are om­ni­vores. An­i­mal prey in­cludes crus­taceans, midges, fish, drag­on­flies, bee­tles, stone­flies, grasshop­pers, and cad­dis­flies. They will eat car­rion as well. The plant por­tion of their diet con­sists pri­mar­ily of wil­low (Salix) and alder catkins (Alnus), tule grass (Scri­pus), ditch grasses (Rup­pi­aceae), pond lily in­flo­res­cences, and green fil­a­men­tous algae. They have been ob­served using a "gape-and-suck" form of tak­ing in small in­ver­te­brates in the water col­umn. Males tend to eat more in­sects and ver­te­brates and fe­males eat more algae and other plant ma­te­r­ial. ("West­ern Pond Tur­tle (Clem­mys Mar­morata)", 2005; "WEST­ERN POND TUR­TLE (Clem­mys mar­morata). Nat­ural His­tory.", 1997; "West­ern Pond Tur­tle: Clem­mys mar­morata", 1999; Bet­tel­heim, 2006)

• Primary Diet
• omnivore

• Animal Foods
• amphibians
• fish
• carrion
• insects
• aquatic crustaceans
• other marine invertebrates

• Plant Foods
• flowers
• algae

Pre­da­tion

Their pri­mary anti-preda­tor adap­ta­tion is their thick cara­pace and wari­ness. At hatch­ing, young tur­tles are both small enough and soft enough to make easy prey, so achiev­ing adult size best pro­tects these tur­tles from pre­da­tion. ("WEST­ERN POND TUR­TLE (Clem­mys mar­morata). Nat­ural His­tory.", 1997; Bet­tel­heim, 2006)

• Known Predators

  • raccoons (Procyon lotor)
  • coyotes (Canis latrans)
  • domestic dogs (Canis lupus familiaris)
  • black bears (Ursus americanus)
  • river otters (Lontra canadensis)
  • mink (Neovison vison)
  • bullfrog (Lithobates catesbeianus)
  • California mountain kingsnakes (Lampropeltis zonata)
  • common kingsnakes (Lampropeltis getula)
  • gopher snakes (Pituophis melanoleucus)
  • yellow-bellied racers (Coluber constrictor)
  • largemouth bass (Micropterus salmoides)
  • spotted skunks (Spilogale putorius)
  • Virginia opossums (Didelphis virginiana)
  • red foxes (Vulpes vulpes)
  • grey fox (Urocyon cinereoargenteus)
  • common ravens (Corvus corax)
  • American crows (Corvus brachyrhynchos)

Ecosys­tem Roles

West­ern pond tur­tles are prey for nu­mer­ous species and preda­tors of other, smaller species. These tur­tles act as hosts for sev­eral par­a­sitic or­gan­isms. ("WEST­ERN POND TUR­TLE (Clem­mys mar­morata). Nat­ural His­tory.", 1997; In­gles, 1930; Reese and Welsh, 1998)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

There is no cur­rent doc­u­mented eco­nomic ben­e­fit of west­ern pond tur­tles. From the 1800s to the 1930s these tur­tles were sold for human con­sump­tion and col­lected for pet trade. This kind of trade is largely il­le­gal today, al­though poach­ing may still occur. ("WEST­ERN POND TUR­TLE (Clem­mys mar­morata). Nat­ural His­tory.", 1997)

• Positive Impacts
• pet trade
• food

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

There are no ad­verse ef­fects of west­ern pond tur­tles on hu­mans.

Con­ser­va­tion Sta­tus

Cur­rent threats to west­ern pond tur­tles are nu­mer­ous and in­clude fire, flood­ing, drought, upper res­pi­ra­tory dis­ease, habi­tat de­struc­tion, and lack of ge­netic vari­a­tion. The lack of vari­a­tion is due to the iso­la­tion of in­di­vid­ual pop­u­la­tions over ranges to large to be cov­ered by mi­gra­tion. Habi­tat de­struc­tion is the re­sult of in­tense ur­ban­iza­tion. Ad­di­tion­ally hu­mans pose a great threat via off-road ve­hi­cles, chem­i­cal spills, and in­ci­den­tal catch by fish­er­men. Lack of re­search has pre­vented west­ern pond tur­tles from being added to the fed­eral en­dan­gered species list. ("West­ern Pond Tur­tle (Clem­mys Mar­morata)", 2005; "West­ern Pond Tur­tle: Clem­mys mar­morata", 1999; Bet­tel­heim, 2006; "West­ern Pond Tur­tle (Clem­mys Mar­morata)", 2004)

Al­though rec­om­mended for the fed­eral en­dan­gered species list, west­ern pond tur­tles are cur­rently only rec­og­nized as state species of spe­cial con­cern by the Cal­i­for­nia De­part­ment of Fish and Game (CDFG). West­ern pond tur­tles have been ex­tir­pated for nearly 20 years in British Co­lum­bia, are listed as en­dan­gered in Wash­ing­ton, and as sen­si­tive with crit­i­cal stand­ing in Ore­gon. ("WEST­ERN POND TUR­TLE (Clem­mys mar­morata). Nat­ural His­tory.", 1997; Gray, 1995)

• IUCN Red List

  Vulnerable
  More information

• IUCN Red List

  Vulnerable
  More information

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  No special status

Other Com­ments

West­ern pond tur­tles are cur­rently rec­og­nized as Emys mar­morata, pre­vi­ously they were rec­og­nized as Clem­mys mar­morata. ("West­ern Pond Tur­tle (Clem­mys Mar­morata)", 2005)

Con­trib­u­tors

Tanya Dewey (ed­i­tor), An­i­mal Di­ver­sity Web.

Joshua Nach­man (au­thor), Uni­ver­sity of Mary­land, Bal­ti­more County, Kevin Om­land (ed­i­tor, in­struc­tor), Uni­ver­sity of Mary­land, Bal­ti­more County.

Ref­er­ences

Of­fice of En­vi­ron­men­tal Health Haz­ard As­s­es­ment. Ex­po­sure Fac­tors for West­ern Pond Tur­tle (Clem­mys mar­morata). Cal­i­for­nia: The Cal­i­for­nia Wildlife Bi­ol­ogy, Ex­po­sure Fac­tor, and Tox­i­c­ity Data­base (Cal/Eco­tox). 1999. Ac­cessed April 22, 2008 at http://​www.​oehha.​ca.​gov/​cal_​ecotox/​report/​clemmef.​pdf.

USDA For­est Ser­vice. WEST­ERN POND TUR­TLE (Clem­mys mar­morata). Nat­ural His­tory.. Red­wood Sci­ences Lab­o­ra­tory: Pa­cific South­west Re­search Sta­tion. 1997. Ac­cessed April 20, 2008 at http://​www.​krisweb.​com/​biblio/​gen_​usfs_​ashtonetal_​1997_​turtle.​pdf.

East Con­tra Costa County HCP/NCCP. West­ern Pond Tur­tle (Clem­mys Mar­morata). Cal­i­for­nia: 2005. Ac­cessed April 20, 2008 at http://​www.​cocohcp.​org/​hcp_​nccp_​content/​hcp_​nccp/​app_​figs/​App%20D%20components/​APP_​D-10a_​Western_​pond_​turtle_​1-18-05.​pdf.​.

Her­petol­ogy North­west. 2004. "West­ern Pond Tur­tle (Clem­mys Mar­morata)" (On-line). Her­petol­ogy North­west. Ac­cessed April 20, 2008 at http://​www.​herpetologynorthwest.​org/​nwherps/​turtles/​western-pond-turtle.​html.

U.S. De­part­ment Of The In­te­rior. West­ern Pond Tur­tle: Clem­mys mar­morata. Cal­i­for­nia: Bu­reau Of Land Man­age­ment. 1999. Ac­cessed April 22, 2008 at http://​www.​blm.​gov/​ca/​pdfs/​cdd_​pdfs/​clemmys1.​PDF.

Bet­tel­heim, M. 2006. "West­ern Pond Tur­tle Nat­ural His­tory" (On-line). At­lantis Mag­a­zine: Re­dis­cov­er­ing Our Lost World. Ac­cessed April 20, 2008 at http://​www.​atlantismagazine.​com/​bettelheim/​pondturtle.​html.

Gray, E. 1995. DNA Fin­ger­print­ing Re­veals a Lack of Ge­netic Vari­a­tion in North­ern Pop­u­la­tions of the West­ern Pond Tur­tle (Clem­mys mar­morata). Con­ser­va­tion Bi­ol­ogy, Vol. 9, No. 5: 1244-1254. Ac­cessed April 20, 2008 at http://​www.​jstor.​org/​stable/​view/​2387062?​seq=2.

In­gles, L. 1930. A New Species of Telorchis from the In­tes­tine of Clem­mys mar­morata. The Jour­nal of Par­a­sitol­ogy, Vol. 17, No. 2: 101-103.

Reese, D., H. Welsh. 1998. Com­par­a­tive De­mog­ra­phy of Clem­mys mar­morata Pop­u­la­tions in the Trin­ity River of Cal­i­for­nia in the Con­text of Dam-in­duced Al­ter­ations. Jour­nal Of Her­petol­ogy, Vol. 32, No. 4: 505-515. Ac­cessed April 20, 2008 at http://​www.​fs.​fed.​us/​psw/​rsl/​projects/​wild/​reese/​reese1x.​PDF.

Reese, D., H. Welsh. 1998. Habi­tat use by west­ern pond tur­tles in the Trin­ity River, Cal­i­for­nia. Jour­nal of Wildlife Man­age­ment, Vol. 62/3: 842-853. Ac­cessed April 20, 2008 at http://​www.​treesearch.​fs.​fed.​us/​pubs/​3654.

Reese, D., H. Welsh. 1997. Use of ter­res­trial habi­tat by west­ern pond tur­tles (Clem­mys mar­morata): im­pli­ca­tions for man­age­ment. Pro­ceed­ings: Con­ser­va­tion, Restora­tion, and Man­age­ment of Tur­tles and Tor­toises. An In­ter­na­tional Con­fer­ence. New York Tur­tle and Tor­toise So­ci­ety.: 352-357. Ac­cessed April 20, 2008 at http://​www.​treesearch.​fs.​fed.​us/​pubs/​3652.