The common snapping turtle (''Chelydra serpentina'') is a

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

of large freshwater

turtle Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked ...

in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Chelydridae. Its natural range extends from southeastern

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tota ...

, southwest to the edge of the

Rocky Mountains The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico in ...

, as far east as

Nova Scotia Nova Scotia ( ; ; ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. Nova Scotia is Latin for "New Scotland". Most of the population are native En ...

and

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, a ...

. The three species of '' Chelydra'' and the larger

alligator snapping turtle The alligator snapping turtle (''Macrochelys temminckii'') is a large species of turtle in the family Chelydridae. The species is native to freshwater habitats in the United States. ''M. temminckii'' is one of the heaviest freshwater turtles i ...

s (genus ''

Macrochelys ''Macrochelys'' is a genus of very large freshwater turtles in the family Chelydridae from Southeastern United States. Only a single extant species was recognized until a 2014 study divided it into two, or possibly three species. Extant species ...

'') are the only extant chelydrids, a family now restricted to the Americas. The common snapping turtle, as its name implies, is the most widespread. The common snapping turtle is noted for its combative disposition when out of the water with its powerful beak-like jaws, and highly mobile head and neck (hence the

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''serpentina'', meaning "

snake Snakes are elongated, limbless, carnivorous reptiles of the suborder Serpentes . Like all other squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with several more j ...

-like"). In water, it is likely to flee and hide underwater in sediment. The common snapping turtle has a life-history strategy characterized by high and variable mortality of embryos and hatchlings, delayed sexual maturity, extended adult longevity, and

iteroparity Semelparity and iteroparity are two contrasting reproductive strategies available to living organisms. A species is considered semelparous if it is characterized by a single reproductive episode before death, and iteroparous if it is characteri ...

(repeated reproductive events) with low reproductive success per reproductive event. Females, and presumably also males, in more northern populations mature later (at 15–20 years) and at a larger size than in more southern populations (about 12 years). Lifespan in the wild is poorly known, but long-term mark-recapture data from Algonquin Park in Ontario, Canada, suggest a maximum age over 100 years.

Anatomy and morphology

''C. serpentina'' has a rugged, muscular build with a ridged

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 und ...

(upper shell), although ridges tend to be more pronounced in younger individuals. The carapace length in adulthood may be nearly , though is more common. ''C. serpentina'' usually weighs . Per one study, breeding common snapping turtles were found to average in carapace length, in plastron length and weigh about . Males are larger than females, with almost all weighing in excess of being male and quite old, as the species continues to grow throughout life. Any specimen above the aforementioned weights is exceptional, but the heaviest wild specimen caught reportedly weighed . Snapping turtles kept in captivity can be quite overweight due to overfeeding and have weighed as much as . In the northern part of its range, the common snapping turtle is often the heaviest native freshwater turtle.Virginia Herpetological Society: Eastern Snapping Turtle ''Chelydra serpentina serpentina''
/ref> Newly hatched common snapping turtles emerging from the ground

Newly hatched common snapping turtles emerging from the ground

Ecology and life history

Common habitats are shallow

pond A pond is an area filled with water, either natural or Artificiality, artificial, that is smaller than a lake. Defining them to be less than in area, less than deep, and with less than 30% Aquatic plant, emergent vegetation helps in disting ...

s or

streams A stream is a continuous body of surface water flowing within the bed and banks of a channel. Depending on its location or certain characteristics, a stream may be referred to by a variety of local or regional names. Long large streams ...

. Some may inhabit

brackish Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...

environments, such as

estuaries An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environme ...

. These sources of water tend to have an abundance of aquatic vegetation due to the shallow pools. Common snapping turtles sometimes bask—though rarely observed—by floating on the surface with only their carapaces exposed, though in the northern parts of their range, they also readily bask on fallen logs in early spring. In shallow waters, common snapping turtles may lie beneath a muddy bottom with only their heads exposed, stretching their long necks to the surface for an occasional breath. Their nostrils are positioned on the very tip of the snout, effectively functioning as snorkels.Hammer, D.A. (1972). ''Ecological relations of waterfowl and snapping turtle populations''. Ph.D. dissertation, Utah State University, Salt Lake City, UT. 72 pg. Snapping turtles are

omnivorous An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nut ...

. Important aquatic scavengers, they are also active hunters that use ambush tactics to prey on anything they can swallow, including many

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% ...

frog A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" '' Triadobatrachus'' is ...

s, reptiles (including snakes and smaller turtles), unwary

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

s, and small mammals. In some areas adult snapping turtles can occasionally be incidentally detrimental to breeding

waterfowl Anseriformes is an order of birds also known as waterfowl that comprises about 180 living species of birds in three families: Anhimidae (three species of screamers), Anseranatidae (the magpie goose), and Anatidae, the largest family, which i ...

, but their effect on such prey as ducklings and goslings is frequently exaggerated. As omnivorous scavengers though, they will also feed on

carrion Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures ...

and a surprisingly large amount of aquatic vegetation. Snapping_turtle_eggs_md

Common snapping turtles have few predators when older, but eggs are subject to predation by

crow A crow is a bird of the genus ''Corvus'', or more broadly a synonym for all of ''Corvus''. Crows are generally black in colour. The word "crow" is used as part of the common name of many species. The related term " raven" is not pinned scientifica ...

American mink The American mink (''Neogale vison'') is a semiaquatic species of mustelid native to North America, though human intervention has expanded its range to many parts of Europe, Asia and South America. Because of range expansion, the American mink ...

skunk Skunks are mammals in the family Mephitidae. They are known for their ability to spray a liquid with a strong, unpleasant scent from their anal glands. Different species of skunk vary in appearance from black-and-white to brown, cream or gi ...

fox Foxes are small to medium-sized, omnivorous mammals belonging to several genera of the family Canidae. They have a flattened skull, upright, triangular ears, a pointed, slightly upturned snout, and a long bushy tail (or ''brush''). Twelv ...

es, and

raccoon The raccoon ( or , ''Procyon lotor''), sometimes called the common raccoon to distinguish it from other species, is a mammal native to North America. It is the largest of the procyonid family, having a body length of , and a body weight o ...

s. As hatchlings and juveniles, most of the same predators will attack them as well as

heron The herons are long-legged, long-necked, freshwater and coastal birds in the family Ardeidae, with 72 recognised species, some of which are referred to as egrets or bitterns rather than herons. Members of the genera ''Botaurus'' and ''Ixobrychu ...

s (mostly

great blue heron The great blue heron (''Ardea herodias'') is a large wading bird in the heron family Ardeidae, common near the shores of open water and in wetlands over most of North America and Central America, as well as the Caribbean and the Galápagos ...

s), bitterns,

hawk Hawks are birds of prey of the family Accipitridae. They are widely distributed and are found on all continents except Antarctica. * The subfamily Accipitrinae includes goshawks, sparrowhawks, sharp-shinned hawks and others. This subfa ...

s, owls, fishers,

American bullfrog The American bullfrog (''Lithobates catesbeianus''), often simply known as the bullfrog in Canada and the United States, is a large true frog native to eastern North America. It typically inhabits large permanent water bodies such as swamps, ...

s, large

, and

snakes Snakes are elongated, limbless, carnivorous reptiles of the suborder Serpentes . Like all other squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with several more j ...

. There are records during winter in

of hibernating adult common snapping turtles being ambushed and preyed on by northern river otters.Brooks, R.J.; Brown, G.P.; Galbraith, D.A. (1991). "Effects of a sudden increase in natural mortality of adults on a population of the common snapping turtle (''Chelydra serpentina'')". ''Canadian Journal of Zoology'' 69 (5): 1314-1320. Other natural predators which have reportedly preyed on adults include

coyote The coyote (''Canis latrans'') is a species of canine native to North America. It is smaller than its close relative, the wolf, and slightly smaller than the closely related eastern wolf and red wolf. It fills much of the same ecological ni ...

American black bear The American black bear (''Ursus americanus''), also called simply a black bear or sometimes a baribal, is a medium-sized bear endemic to North America. It is the continent's smallest and most widely distributed bear species. American black bea ...

American alligator The American alligator (''Alligator mississippiensis''), sometimes referred to colloquially as a gator or common alligator, is a large crocodilian reptile native to the Southeastern United States. It is one of the two extant species in the ...

s and their larger cousins,

s. Large, old male snapping turtles have very few natural threats due to their formidable size and defenses, and tend to have a very low annual mortality rate. These turtles travel extensively over land to reach new

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

s or to lay eggs. Pollution,

habitat destruction Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...

, food scarcity, overcrowding, and other factors drive snappers to move; it is quite common to find them traveling far from the nearest water source. Experimental data supports the idea that snapping turtles can sense the Earth's magnetic field, which could also be used for such movements (together with a variety of other possible orientation cues). This species mates from April through November, with their peak laying season in June and July. The female can hold sperm for several seasons, using it as necessary. Females travel over land to find sandy soil in which to lay their eggs, often some distance from the water. After digging a hole, the female typically deposits 25 to 80 eggs each year, guiding them into the

nest A nest is a structure built for certain animals to hold eggs or young. Although nests are most closely associated with birds, members of all classes of vertebrates and some invertebrates construct nests. They may be composed of organic materi ...

with her hind feet and covering them with sand for incubation and protection. Incubation time is temperature-dependent, ranging from 9 to 18 weeks. One study on the incubation period of the common snapping turtle incubated the eggs at two temperatures: 20 °C (68 °F) and 30 °C (86 °F). The research found that the incubation period at the higher temperature was significantly shorter at approximately 63 days, while at the lower temperature the time was approximately 140 days. In cooler climates, hatchlings overwinter in the nest. The common snapping turtle is remarkably cold-tolerant; radiotelemetry studies have shown some individuals do not hibernate, but remain active under the ice during the winter. Common snapping turtle hatchlings have recently been found to make sounds before nest exit onto the surface, a phenomenon also known from species in the South American genus '' Podocnemis'' and the

Ouachita map turtle The Ouachita map turtle (''Graptemys ouachitensis'') is a species of turtle belonging to the family Emydidae. Subspecies Subspecies include: * ''Graptemys ouachitensis ouachitensis'' Cagle, 1953 * ''Graptemys ouachitensis sabinensis'' Cagle ...

. These sounds are mostly "clicking" noises, but other sounds, including those that sound somewhat like a “creak” or rubbing a finger along a fine-toothed comb, are also sometimes produced. In the northern part of their range snapping turtles do not breathe for more than six months because ice covers their hibernating site. These turtles can get oxygen by pushing their head out of the mud and allowing gas exchange to take place through the membranes of their mouth and throat. This is known as extrapulmonary respiration. If they cannot get enough oxygen through this method they start to utilize anaerobic pathways, burning sugars and fats without the use of oxygen. The metabolic by-products from this process are acidic and create very undesirable side effects by spring, which are known as oxygen debt. Although designated as "least concern" on the IUCN redlist, the species has been designated in the Canadian part of its range as "Special Concern" due to its life history being sensitive to disruption by anthropogenic activity.

Systematics and taxonomy

Currently, no subspecies of the common snapping turtle are recognized. The former Florida subspecies ''osceola'' is currently considered a synonym of ''serpentina'', while the other former subspecies ''

Chelydra rossignonii The Central American snapping turtle (''Chelydra rossignonii''), also known commonly as the Mexican snapping turtle and the Yucatan snapping turtle, is a species of turtle in the family Chelydridae. The species is endemic to Central America and ...

'' and ''

Chelydra acutirostris The South American snapping turtle (''Chelydra acutirostris'') is a species of turtle in the family Chelydridae. This species, which is endemic to Central and northwestern South America, was previously considered a subspecies of ''Chelydra serpe ...

'' are both recognized as full species.

Behavior

In their environment, they are at the top of the food chain, causing them to feel less fear or aggression in some cases. When they encounter a species unfamiliar to them such as humans, in rare instances, they will become curious and survey the situation and even more rarely may bump their nose on a leg of the person standing in the water. Although snapping turtles have fierce dispositions, when they are encountered in the water or a swimmer approaches, they will slip quietly away from any disturbance or may seek shelter under mud or grass nearby.Common Snapping Turtle
Nature.ca

Relationship with humans

As food

The common snapping turtle is a traditional ingredient in turtle soup; consumption in large quantities, however, can become a health concern due to potential concentration of toxic environmental pollutants in the turtle's flesh.

Captivity

The common snapping turtle is not an ideal pet. Its neck is very flexible, and a wild turtle can bite its handler even if picked up by the sides of its shell. The claws are as sharp as those of

bears Bears are carnivoran mammals of the family Ursidae. They are classified as caniforms, or doglike carnivorans. Although only eight species of bears are extant, they are widespread, appearing in a wide variety of habitats throughout the Nor ...

and cannot be trimmed as can dog claws. The turtle uses its paws like a bear for hunting and slicing food, while biting it. Despite this, a snapping turtle cannot use its claws for either attacking (its legs have no speed or strength in "swiping" motions) or eating (no opposable thumbs), but only as aids for digging and gripping. Veterinary care is best left to a reptile specialist. A wild common snapping turtle will make a hissing sound when it is threatened or encountered, but they prefer not to provoke confrontations. It is a common misconception that common snapping turtles may be safely picked up by the tail with no harm to the animal; in fact, this has a high chance of injuring the turtle, especially the tail itself and the

vertebra The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characterist ...

l column. Lifting the turtle with the hands is difficult and dangerous. Snappers can stretch their necks back across their own carapace and to their hind feet on either side to bite. When they feel stressed, they release a musky odor from behind their legs. It may be tempting to rescue a snapping turtle found on a road by getting it to bite a stick and then dragging it out of immediate danger. This action can, however, severely scrape the legs and underside of the turtle and lead to deadly infections in the wounds. The safest way to pick up a common snapping turtle is by grasping the carapace behind the back legs, being careful to not grasp the tail. There is a large gap behind the back legs that allows for easy grasping of the carapace and keeps hands safe from both the beak and claws of the turtle. It can also be picked up with a shovel, from the back, making sure the shovel is square across the bottom of the shell. The easiest way, though, is with a blanket or tarp, picking up the corners with the turtle in the middle. Snapping turtles are raised on some turtle farms in Mainland China.

In politics

The common snapping turtle was the central feature of a famous American political cartoon. Published in 1808 in protest at the Jeffersonian

Embargo Act of 1807 The Embargo Act of 1807 was a general trade embargo on all foreign nations that was enacted by the United States Congress. As a successor or replacement law for the 1806 Non-importation Act and passed as the Napoleonic Wars continued, it re ...

, the cartoon depicted a snapping turtle, jaws locked fiercely to an American trader who was attempting to carry a barrel of goods onto a British ship. The trader was seen whimsically uttering the words "Oh! this cursed Ograbme" ("

embargo Economic sanctions are commercial and financial penalties applied by one or more countries against a targeted self-governing state, group, or individual. Economic sanctions are not necessarily imposed because of economic circumstances—they ...

" spelled backwards, and also "O, grab me" as the turtle is doing). This piece is widely considered a pioneering work within the

genre Genre () is any form or type of communication in any mode (written, spoken, digital, artistic, etc.) with socially-agreed-upon conventions developed over time. In popular usage, it normally describes a category of literature, music, or other ...

of the modern political cartoon. In 2006, the common snapping turtle was declared the state reptile of

New York New York most commonly refers to: * New York City, the most populous city in the United States, located in the state of New York * New York (state), a state in the northeastern United States New York may also refer to: Film and television * '' ...

by vote of the New York Legislature after being chosen by the state's public

elementary school A primary school (in Ireland, the United Kingdom, Australia, Trinidad and Tobago, Jamaica, and South Africa), junior school (in Australia), elementary school or grade school (in North America and the Philippines) is a school for primary ed ...

children.

Reputation

While it is widely rumored that common snapping turtles can bite off human fingers or toes, and their powerful jaws are more than capable of doing so, no proven cases have ever been presented for this species, as they use their overall size and strength to deter would-be predators. Common snapping turtles are "quite docile" animals underwater that prefer to avoid confrontations rather than provoke them. In 2002, a study done in the ''

Journal of Evolutionary Biology The ''Journal of Evolutionary Biology'' is a peer-reviewed scientific journal published monthly covering the field of evolutionary biology. It is owned by the European Society for Evolutionary Biology. The founding editor-in-chief was Stephen C. ...

'' found that the common snapping turtle (''Chelydra serpentina'') registered between 208 and 226

Newtons The newton (symbol: N) is the unit of force in the International System of Units (SI). It is defined as 1 kg⋅m/s, the force which gives a mass of 1 kilogram an acceleration of 1 metre per second per second. It is named after Isaac Newton in ...

of force when it came to jaw strength. In comparison, the average bite force of a human ( molars area) is between 300 and 700 Newtons. Another non-closely related species known as the

has been known to bite off fingers, and at least three documented cases are known.

Invasive species

In recent years in

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...

, large mature adult ''C. serpentina'' turtles have been taken from bodies of water throughout the country. They were most probably introduced by the release of unwanted pets. In March 2011, an individual weighing was captured in a canal near

Rome , established_title = Founded , established_date = 753 BC , founder = King Romulus ( legendary) , image_map = Map of comune of Rome (metropolitan city of Capital Rome, region Lazio, Italy).svg , map_caption ...

; another individual was captured near Rome in September 2012. In Japan, the species was introduced as an exotic pet in the 1960s; it has been recorded as the source of serious bite injuries. In 2004 and 2005, some 1,000 individuals were found in

Chiba Prefecture is a prefecture of Japan located in the Kantō region of Honshu. Chiba Prefecture has a population of 6,278,060 (1 June 2019) and has a geographic area of . Chiba Prefecture borders Ibaraki Prefecture to the north, Saitama Prefecture to the n ...

, making up the majority of individuals believed to have been introduced.

Conservation

The species is currently classified as

Least Concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. Th ...

by the IUCN, but has declined sufficiently due to pressure from collection for the pet trade and habitat degradation that Canada and several U.S. states have enacted or are proposing stricter conservation measures. In Canada, it is listed as "Special Concern" in the Species at Risk Act in 2011 and is a target species for projects that include surveys, identification of major habitats, investigation and mitigation of threats, and education of the public including landowners. Involved bodies include governmental departments, universities, museums, and citizen science projects. Although Common snapping turtles are listed as a species of least concern, anthropogenic factors still may have major effects on populations. Decades of road mortality may cause severe population decline in common snapping turtle populations present in urbanized wetlands. A study in southwestern Ontario monitored a population near a busy roadway and found a loss of 764 individuals in only 17 years. The population decreased from 941 individuals in 1985 to 177 individuals in 2002. Road mortality may put common snapping turtle populations at risk of extirpation. Exclusion fencing could aid in decreasing population loss.

References

External links

The Snapping Turtle Page - www.chelydra.orgVideo: How to Help a Snapping Turtle Cross a Road
Toronto Zoo
Snapping Turtle
Reptiles and Amphibians of Iowa