|Scientific Name:||Chelydra serpentina|
|Species Authority:||(Linnaeus, 1758)|
Chelydra osceola Stejneger, 1918
Testudo serpentina Linnaeus, 1758
|Taxonomic Notes:||Two subspecies (Chelydra serpentina serpentina (Linnaeus, 1758) and C. s. osceola Stejneger, 1918) were recognized until osceola was synonymized with serpentina by Shaffer et al. (2008), based on lack of significant genetic differentiation. Phillips et al. (1996) removed the former subspecies rossignoni and acutirostris by elevating these to species level, based on genetic differentiation.|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor/s:||van Dijk, P.P.|
|Reviewer/s:||Horne, B.D., Mittermeier, R.A., Philippen, H.-D., Quinn, H.R., Rhodin, A.G.J., Shaffer, H.B. & Vogt, R.C|
While the Snapping Turtle is widely exploited and impacted by a wide variety of other factors, the species is adaptable and widespread, and has a relatively high reproductive potential. Local declines have been documented, but overall the species does not approach a 30 percent range-wide decline over three generations (likely around 50 years), nor is it likely to approach this level in the near future. As such, the species is assessed as Least Concern.
|Range Description:||Chelydra serpentina ranges throughout North America east of the Rocky Mountains, occurring northwards as far as the Great Lakes region and Nova Scotia, and southwards as far as Florida and the Nueces river (Texas) (Iverson 1992, Ernst and Lovich 2009). Feral turtles have been recorded from California (US), Japan, the Netherlands, Taiwan, and the United Kingdom.|
Native:Canada (Manitoba, New Brunswick, Nova Scotia, Ontario, Québec, Saskatchewan); United States (Alabama, Arizona - Introduced, Arkansas, California - Introduced, Colorado, Connecticut, Delaware, District of Columbia, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada - Introduced, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon - Introduced, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Vermont, Virginia, West Virginia, Wisconsin, Wyoming)
Introduced:China; Japan; Taiwan, Province of China
|Range Map:||Click here to open the map viewer and explore range.|
Chelydra serpentina is widely distributed across a variety of habitats. It is never the numerically dominant turtle species, but it usually represents about 2–12% of the total number of turtles in trapping studies. Given its large body size, at its reported densities of 1.2–49 animals or 19–166 kg per hectare of suitable habitat, its biomass and presumably its ecological significance are substantial.
In Michigan, Snapping Turtles were intensively trapped for 2–3 years in the 1980s, greatly reducing populations. By 2009 populations were approaching pre-impact levels, indicating a 25–30 year recovery period after depletion (J. Harding pers comm. Aug 2009).
|Habitat and Ecology:||
Chelydra serpentina inhabits almost any type of water body, from rivers, lakes and reservoirs to marshes, temporary ponds, hill streams and tidal creeks. It ranges from tidally-influenced lowlands to 2,000 m altitude.
Snapping Turtles feed on a wide variety of animal and plant matter, and undergo extensive scavenging activities. At reported densities of 1.2–49 animals or 19–166 kg per hectare of suitable habitat, its biomass and presumably its ecological significance are substantial.
Males reach 49.4 cm carapace length (CL), females 36.6 cm CL. Maturity is reached at at 4–6 yrs and 18–19 cm CL in males, and at about 10–12 (range 9–18) years / 20–22 (19–29) cm CL in females. Longevity 25–30 years (max 40 yrs). They usually produce a single clutch of 25–45 eggs (number of eggs increases with latitude) (Ernst and Lovich 2009). Generation time apparently has not been calculated. Incubation commonly takes 75–95 days. Hatchlings measure about 29 mm on average (range 16–38 mm).
[Information taken from reviews by Aresco et al. 2006, Steyermark et al. 2008, Ernst and Lovich 2009].
Chelydra serpentina is widely exploited, in some areas at the northern limits of occurrence to the degree that populations have declined significantly. As a result, Canada and many states in the U.S. have brought the species under various degrees of regulation or legislation to manage exploitation and trade, with a regulated or unrestricted commercial offtake permitted in about half the states in which the species occurs. Collection of Snapping Turtles from the wild, and captive production in turtle farms, for export to East Asia increased substantially in recent years, from about 10,000 animals declared as exported from the USA in 1999 to over 300,000 annually in recent years (LEMIS database - total recorded export numbers: 1999 – 10,053; 2000 – 18,486; 2001 – 38,911; 2002 – 63,644; 2003 – 129,683; 2004 – 141,544; 2005 – 316,500; 2006 – 377,408; 2007 – 316,093; 2008 – 558,491; available data do not allow differentiation of farmed vs. wild-collected trade volumes).
While habitat loss and degradation likely affect individuals and populations, Snapping Turtles are adaptable and mobile and are unlikely to be threatened by habitat change processes.
The impact of 'subsidized' predators (i.e., unnaturally large populations of predators subsidized by easily available resources near human settlements) is generally unquantified but may be significant.
The impact of pollution, particularly of pesticides, industrial chemicals, and heavy metals, on Snapping Turtles appears to be sub-lethal at worst, to the point that snappers are a recognized biomonitoring species to monitor accumulation of pollutants in aquatic ecosystems.
Road-kill and other casual human-induced mortality occurs, but it is not clear whether this represents an overall threat to the species in combination with other impacts.
Chelydra serpentina is subject to a variety of state legislation, regulations and management efforts in Canada and the United States.
Capture of the species from the wild is prohibited in Michigan and a number of other states, capture is permitted under regulation (size and/or bag limits, closed seasons, area restrictions, gear restrictions, restrictions on commercial use, etc.) in Alabama, Maryland, New York, Texas and several other states, and capture is unregulated in a few state.
Throughout the United States, trade in the species is restricted to animals over four inches CL, reducing the casual pet trade and making turtles under four inches CL available only for educational purposesThe Snapping Turtle occurs in a substantial number of protected areas, both public and private.
|Citation:||van Dijk, P.P. 2012. Chelydra serpentina. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 21 May 2013.|
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