Emys Marmorata
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The western pond turtle (''Actinemys marmorata''), also known commonly as the Pacific pond turtle is a
species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
of small to medium-sized
turtle Turtles are reptiles of the order (biology), order Testudines, characterized by a special turtle shell, shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Crypt ...
in the
family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
Emydidae Emydidae (Latin (freshwater tortoise) + Ancient Greek (, "appearance, resemblance")) is a family of testudines (turtles) that includes close to 50 species in 10 genera. Members of this family are commonly called terrapins, pond turtles, or mar ...
. The species is
endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...
to the western coast of the United States and Mexico, ranging from western Washington state to northern
Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...
. It was formerly found in
Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...
(in
British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...
), but in May 2002, the Canadian
Species at Risk Act The ''Species at Risk Act'' (, SARA) is a piece of Canadian federal legislation which became law in Canada on December 12, 2002. It is designed to meet one of Canada's key commitments under the International Convention on Biological Diversity. T ...
listed the Pacific pond turtle as being
extirpated Local extinction, also extirpation, is the termination of a species (or other taxon) in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinctions. Local extinctions mark a chan ...
.


Taxonomy and systematics

Its genus classification is mixed. ''
Emys ''Emys'' is a small genus within the family Emydidae. The genus ('' sensu lato''), consisting primarily of freshwater pond turtles, is endemic to Europe. It is the only genus in the Emydidae outside of North America. Species The following two ...
'' and ''
Actinemys ''Actinemys'' is a small genus of turtles in the family Emydidae."''Actinemys'' ". The Reptile Database. www.reptile-database.or The genus is Endemism, endemic to the west coast of North America. The genus contains two species. Species The fol ...
'' were used among published sources in 2010. It was known by several names in the Indigenous languages of its range, including kʰá:wanaka: (
Northeastern Pomo Northeastern Pomo, also known as Salt Pomo, is a Pomoan language of Northern California. There are no living fluent speakers. It was spoken along Stony Creek, a tributary of the Sacramento River. Northeastern was one of seven mutually unintellig ...
), kʰa:wana (
Southern Pomo Southern Pomo is one of seven mutually unintelligible Pomoan languages which were spoken by the Pomo people in Northern California along the Russian River and Clear Lake. The Pomo languages have been grouped together with other so-called Hokan ...
), and ʔaləšək (
Lushootseed Lushootseed ( ), historically known as Puget Salish, Puget Sound Salish, or Skagit-Nisqually, is a Central Coast Salish language of the Salishan language family. Lushootseed is the general name for the dialect continuum composed of two main di ...
).


Description

The
dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage The fus ...
color of ''A. marmorata'' is usually dark brown or dull olive, with or without darker reticulations or streaking. The
plastron The turtle shell is a shield for the ventral and dorsal parts of turtles (the Order (biology), order Testudines), completely enclosing all the turtle's vital organs and in some cases even the head. It is constructed of modified bony elements such ...
is yellowish, sometimes with dark blotches in the centers of the scutes. The straight
carapace A carapace is a dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the unde ...
length is . The carapace is low and broad, usually widest behind the middle, and in adults is smooth, lacking a keel or serrations. Adult western pond turtles are sexually dimorphic, with males having a light or pale yellow throat.


Distribution

The western pond turtle originally ranged from northern
Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...
, Mexico, north to the southern regions of
British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...
, Canada. It was once a large part of a major fishery on
Tulare Lake Tulare Lake () or Tache Lake ( Yokuts: ''Pah-áh-su'', ''Pah-áh-sē'') is a freshwater lake in the southern San Joaquin Valley, California, United States. Historically, Tulare Lake was once the largest freshwater lake west of the Mississippi R ...
, California, supplying San Francisco with a local favorite, turtle soup, as well as feed for hogs that learned to dive for it in the shallows of Hog Island, also on Tulare Lake. As of 2007, it has become rare or absent in the
Puget Sound Puget Sound ( ; ) is a complex estuary, estuarine system of interconnected Marine habitat, marine waterways and basins located on the northwest coast of the U.S. state of Washington (state), Washington. As a part of the Salish Sea, the sound ...
region of
Washington Washington most commonly refers to: * George Washington (1732–1799), the first president of the United States * Washington (state), a state in the Pacific Northwest of the United States * Washington, D.C., the capital of the United States ** A ...
. It has a disjunct distribution in most of the Northwest, and some isolated populations exist in southern Washington. The western pond turtle is now rare in the
Willamette Valley The Willamette Valley ( ) is a valley in Oregon, in the Pacific Northwest region of the United States. The Willamette River flows the entire length of the valley and is surrounded by mountains on three sides: the Cascade Range to the east, the ...
north of
Eugene, Oregon Eugene ( ) is a city in and the county seat of Lane County, Oregon, United States. It is located at the southern end of the Willamette Valley, near the confluence of the McKenzie River (Oregon), McKenzie and Willamette River, Willamette rivers, ...
, but abundance increases south of that city where temperatures are higher. It may be locally common in some streams, rivers and ponds in southern Oregon. A few records are reported east of the
Cascade Mountains The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as many of those in the ...
, but these may have been based on introduced individuals. It ranges up to in Washington, and to about in Oregon. It also occurs in Uvas Canyon area, Santa Cruz Mountains, California, and in the North Bay, and lakes such as Fountaingrove Lake. Many taxonomic authorities now split what had been considered one species of turtle into two species. The southern species is named ''
Actinemys pallida ''Actinemys pallida'', the southwestern pond turtle, is an aquatic turtle of the genus ''Actinemys'' in the family ''Emydidae''. It can be found in bodies of water in southern California and Baja California. References pallida This list ...
'', or the southwestern pond turtle. Its range is southern California and Mexico. The northern species remains ''Actinemys marmorata'', with a range of northern California northward. It is then usually referred to as the northwestern pond turtle.


Ecology and behavior

The western pond turtle occurs in both permanent and intermittent waters, including marshes, streams, rivers, ponds, and lakes. It favors habitats with large numbers of emergent logs or boulders, where individuals aggregate to bask. They also bask on top of aquatic vegetation. Consequently, this species is often overlooked in the wild. However, it is possible to observe resident turtles by moving slowly and hiding behind shrubs and trees. ''A. marmorata'' can be encouraged to use artificial basking substrate, or rafts, which allows for easy detection of the species in complex habitats. In addition to its aquatic habitat, terrestrial habitat is also extremely important for the western pond turtle. Since many intermittent ponds can dry up during summer and fall months along the west coast, especially during times of drought, the western pond turtle can spend upwards of 200 days out of water. Many turtles overwinter outside of the water, during which time they often create their nests for the year. Overwintering sites can sometimes be 500 meters from a main body of water


Diet

The western pond turtle is
omnivorous An omnivore () is an animal that regularly consumes significant quantities of both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize ...
and most of its animal diet includes insects, crayfish, and other aquatic invertebrates. Fish, tadpoles, and frogs are eaten occasionally, and carrion is eaten when available. Plant foods include filamentous algae, lily pads, tule and cattail roots. Juveniles are primarily carnivorous, and eat insects and carrion. At about age three they begin to eat plant matter.


Predation and threat

Raccoons, otters, ospreys, and coyotes are the biggest natural threats to this turtle, its eggs, and hatchlings. Weasels and large fish are also known predators. Non-native predators include bullfrogs, crayfish, and opossums. In the past the turtle was exploited as food by both indigenous peoples and American settlers. After the goldrush in California a large "fishery" emerged processing turtles from the San Francisco Bay Estuary into canned soup for markets East. Finally, this species is still threatened by humankind. Due to
habitat destruction Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...
and modification, this species is currently listed as vulnerable on the
IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...
and by
NatureServe NatureServe, Inc. is a non-profit organization based in Arlington County, Virginia, United States, US, that provides proprietary wildlife conservation-related data, tools, and services to private and government clients, partner organizations, and ...
. It also faces significant competition from introduced invasive species, especially the red-eared slider. With the removal of ponds, modification of sandy banks needed for egg laying, draining of wetlands, this species is now vulnerable. Efforts at reintroducing this turtle to its native range have met with limited success.


Reproduction

Sexually mature females of the western pond turtle produce 5–13 eggs per
clutch A clutch is a mechanical device that allows an output shaft to be disconnected from a rotating input shaft. The clutch's input shaft is typically attached to a motor, while the clutch's output shaft is connected to the mechanism that does th ...
. They deposit eggs either once or twice a year. They may travel some distance from water for egg-laying, moving as much as 0.8 km (1/2 mile) away from and up to above the nearest source of water, but most nests are within of water. The female usually leaves the water in the evening and may wander far before selecting a nest site, often in an open area of sand or hardpan that is facing southwards. The nest is flask-shaped with an opening of about . Females spend considerable time covering up the nest with soil and adjacent low vegetation, making it difficult for a person to find unless it has been disturbed by a predator.


Hatchlings

The vast majority of western pond turtle hatchlings overwinter in the nest, and this phenomenon seems prevalent in most parts of the range, especially northern areas. This might explain the difficulty researchers have had in trying to locate hatchlings in the fall months. Winter rains may be necessary to loosen the hardpan soil where some nests are deposited. It may be that the nest is the safest place for hatchlings to shelter while they await the return of warm weather. Whether it is hatchlings or eggs that overwinter, young first appear in the spring following the year of egg deposition. Individuals grow slowly in the wild, and their age at their first reproduction may be 10 to 12 years in the northern part of the range. The western pond turtle may survive more than 50 years in the wild.


References


Bibliography

*Holland, Dan C., PhD. The Western Pond Turtle: Habitat and History, Final Report. U.S. Department of Energy, Bonneville Power Administration, Division of Fish and Wildlife; Wildlife Diversity Program, Oregon Department of Fish and Wildlife, August 1994. * *


Further reading

* Baird SF, Girard CF (1852). "Descriptions of new species of Reptiles, collected by the U. S. Exploring Expedition under the command of Capt. Charles Wilkes, U. S. N. First part.—Including the species from the Western coast of America". ''Proc. Acad. Nat. Sci. Philadelphia'' 6: 174–177. (''Emys marmorata'', new species, p. 177). *Seidel, Michael E.; Ernst, Carl H. (2017). "A Systematic Review of the Turtle Family Emydidae". ''Vertebrate Zoology'' 67 (1): 1–122. (''Actinemys marmorata'', pp. 36–38, Figure 36).


External links


Field Identification: Guide to Distinguishing Western Pond Turtles (''Actinemys'' spp.) from Common Pond Sliders (''Trachemys'' spp.)
{{Authority control Emys Actinemys Turtles of North America Reptiles of Mexico Reptiles of the United States Fauna of the Western United States Fauna of the San Francisco Bay Area Reptiles described in 1852 Taxa named by Spencer Fullerton Baird Taxa named by Charles Frédéric Girard