Physical Description
The Alligator snapping turtle is a unique species, the only one of its kind that shares a genetic background with the extinct prehistoric Carbonemys cofrinii. The Alligator snapper is a massive turtle that can easily crush other turtles in half because of the colossal size and enormously strong jaw bones. The species is sometimes described as dinosaur-like because of its primitive-looking appearance and spiky shell. Unlike all other species of the snapping turtles, the Alligator snapper has eyes located on both of its sides. It is the largest freshwater turtle that typically weighs between 45-175 lb and generally attains an average length of 1.1-2.6 ft.
Primitive-looking Alligator Snapping Turtle
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Image credits: reptiles4all/Shutterstock
While being one of the heaviest turtles on earth on average, there have been findings of even larger specimens like the 16-year-old resident giant Alligator snapper in 1999 that weighed 249 lb at the Tennessee Aquarium. Another weighing 236 lb was housed at the Brookfield Zoo in Chicago that reached a maximum carapace length of 2.8 feet. There is sexual dimorphism within the species where the male adult is larger than the female snapper and also the position of the cloaca varies per gender. The lifespan of a typical Alligator snapping turtle can be anywhere between 11 – 45 years although a few examples have been recorded to live as long as 70 years.
Geographical Distribution
The Alligator snapping turtle is native to the North American continent and is located in freshwater habitats and wetland swamps. They are primarily situated in the southeastern United States occupying regions like northern Florida, eastern Texas, southeastern Iowa, western Illinois and southern Georgia. They can be found also north to southeastern Kansas, northern Gavin’s Point Dam, western Tennessee, southern Indiana, western Kentucky and across the Missouri River at Yankton, South Dakota.
Habitat
Alligator snappers prefer a freshwater habitat and are usually living in deep waters of large rivers, lakes, canals and swamps. While hatchlings are bred near surface water and near smaller streams, adults are generally confined to river systems that drain in the Gulf of Mexico. Male alligator snappers spend most of their time underwater whereas females generally venture on land during the breeding season. The species resides in a temperate climatic zone that consists of marshy fields, freshwater river beds and brackish wetlands.
Anatomy
Alligator snapping turtles are known as the ‘dinosaurs of the turtle world’ because of their prehistoric appearance. The rugged, spiky carapace or ridged upper shell camouflages brilliantly in the wild, making the Alligator snapper an elegant predator. The species has a large head, powerful built, hooked beak like jaws, oversized claws and a scaly, rough skin that sets it apart from other freshwater turtles.
Spiky carapace of the Alligator Snapping Turtle
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Image credits: Sista Vongjintanarug/Shutterstock
The three large pronounced ridges, that run across the full back of its dark-brown to blackish shell, resemble the rugged skin of an alligator. The Alligator snapper showcases bilateral symmetry and is, like all reptiles, an ectothermic being. This colossal predator is omnivorous and feeds on both plants as well as the flesh of invertebrates, aquatic crustaceans and fish. Though it is known as the alligator snapping turtle, the bite force recorded is lesser as compared to other turtles and is almost equivalent to a human’s bite force relative to the turtle’s body size. The species is capable of biting through the handle of a broom and there are rare cases where human fingers have also been bitten off.
Sexual dimorphism is apparent in the species by the distinct location of the cloaca on the male and female snapper. In female alligator snappers the cloaca is based on the edge of the carapace whereas in males the cloaca extends beyond the edge of the carapace. The tail is as long as the shell itself however the size differs in both male and female alligator snappers. Apart from size, the base of the tail in males is thicker as compared to females because of the reproductive organs that are hidden. Together with the chin, neck and throat, the skin is coated with long, pointed tubercles. The interior of the turtle’s mouth is camouflaged and there is a vermiform appendage (worm-shaped appendage) located at the tip of the tongue which is used to lure fish, an adaptation known as the Peckhamian mimicry. This appendage is generally grey at first but suffused with blood that is wriggled to attract prey into the turtle’s mouth. The shell of the turtle often has algae growing on it that help the animal to camouflage itself in the wild.
Feeding Habits
The alligator snapping turtle is an omnivore that consumes both meat and plants although it prefers invertebrates and fish more often. It is an opportunistic feeder that relies on both living foods as well as dead organisms which it can scavenge. In general, the species eat almost anything they can get their hands on. The alligator snapping turtle generally prefers to catch prey, like for example fish, that is abundant and easy to prey on. Their diet primarily consists of fish and fish carcasses, mollusks, carrion, crustaceans and amphibians. They are also known to prey on snakes, crayfish, worms, aquatic plants, water birds and other turtles. On certain occasions the species may also prey on aquatic rodents, muskrats, nutrias and small to mid-sized mammals like squirrels, opossums and armadillos caught mostly near the water’s edge.
The snapper uses its tongue to lure prey near enough for a strike.
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Image credits: Ryan M. Bolton/Shutterstock
Alligator snapping turtles are nocturnal hunters, primarily being active at night when the temperature conditions are suitable. During the day they lie quietly at the bottom of murky water keeping their jaws open and waiting for their prey. The snapper uses its tongue to lure prey near enough for a strike. The tongue is wriggled to mimic the movements of a worm that generally attracts fish and several invertebrates towards the predator. Young alligator snappers use this technique to catch small fish like minnows. Adults, however, must forage more actively to satisfy their voracious appetites.
They also use certain sensory organs to detect prey by tasting chemicals in the water that indicate the presence of a certain species. Another regular food source for alligator snappers are plants like nuts, seeds, wood, bark, roots, leaves or stems.
Predator
Alligator snapping turtles are large enough to be considered major predators in the wild. However, despite their size and rocky built, also this species face certain threats, especially from humans. Hatchlings are often preyed on by raccoons, predatory fish, large birds and freshwater alligators. Humans find the alligator snapping turtle quite valuable for its meat and appearance. As a consequence, illegal trade and hunting are common problems for this species.
Reproduction
The mating season for Alligator snapping turtles begins in early spring in the southern part of the continent like Florida and late spring in northern ends like Mississippi Valley. The species is polygynandrous which means both male and female snappers mate with more than one partner. The breeding is seasonal and it takes place once a year. The species reaches sexual maturity within 11 – 13 years. During the breeding season, Alligator snappers are quite territorial and upon finding a potential female mate, they mount the back of the female as a form of showing their approval. They grasp the shell of the female snapper using their sharp, crooked feet to induce insemination. The fertilization is oviparous where the female lays eggs in a nest, which is a dug hole approximately 50 m from a water source. The nest is dug in the sand and the clutch size depends upon various factors.
A clutch may contain as many as 8 – 52 eggs and incubation generally persists for 100 – 140 days. Hatchlings tend to be born in the fall and are independent at birth which is also why they often become easy prey for vicious predators. The sexual orientation of the newborn depends on the incubation temperature. The newborn alligator snappers are very similar to adults in terms of their appearance. Where females generally are born if the incubation temperature is around 29 – 30 degree Celsius, males are born when a lower incubation temperature condition of 25 – 27 degree Celsius has existed. Baby alligator snapper turtles feed on snails, guppies, tadpoles, crayfish and other small invertebrates in the water.
Behavior
Alligator snapping turtles are massive predators with a primitive appearance, hence they are also known as the ‘dinosaurs of the turtle world’.
Initially, it was considered that the Alligator snapping turtle had two more subspecies. However, today all three have been differentiated into three separate species. They are the largest freshwater turtles found in North American waters that spend most of their time in the water and generally only come out to bask in the sun. They are solitary creatures that show little to less parental care. While adult alligator snappers reside in rivers, swamps and canals, the hatchlings stay near small streams. The most distinguishing feature of the species is the presence of three dorsal ridges of large scales on the shell that give it a prehistoric appearance. With radiating yellow patterns around the eyes and algal growth on the carapace, the species gets naturally camouflaged in the wild.
Radiated eye pattern of the Alligator Snapping Turtle
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Image credits: Webitect/Shutterstock
The alligator snapping turtle is an ambush predator that waits to catch its prey in water and generally luring the prey using its tongue. A fascinating adaptation of the Alligator snapper is its tongue that is shaped like a worm which it wriggles to attract prey. The Macrochelys temminckii is a bottom feeder that is mostly active at night and is known to feed often on decaying remains. Alligator snappers generally eat all year round. However, they refuse to eat when the temperature is high and therefore prefers a warm winter season to search for food in water and along the shoreline. The species shows seasonal migration where a few populations are known to make extended movements at particular times of the year for finding hibernation sites and breeding grounds. Even though they migrate on a local base, older individuals generally move upstream as years pass by. The species is quite aggressive when defending itself and shows very little social interaction.
The Snapping turtle is quite aggressive when defending itself
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Image credits: Ryan M. Bolton/Shutterstock
Generally, if an Alligator snapping turtle is forced to leave its resting spot it becomes agitated and very aggressive. If attacked or picked up the snapper will shoot its head forward with incredible speed and will use its enormous jaw to bite. It extends its neck forward and closes its jaws with a loud crunch grabbing onto its attacker with a bite force that can easily deliver a painful wound. Sometimes the species also likes to bury themselves in the mud with only its nostrils and eyes exposed, which is another adaptation to catch prey. Principle predators of the alligator snapper are humans which is why the species has become elusive and shows secretive traits. In terms of communication, the alligator snapper uses chemosensory cues to locate its prey. They use throat (gular) pumping to draw in water for sampling changes in the surroundings. They also use certain leg movements to communicate with their mates in the breeding season.
Threats
Alligator snapping turtles have no natural predators in their native environment. However, due to human interference the population has suffered a massive decline. The species is hunted by poachers for its meat and the shell. Major exploitation of the species is also being caused by trappers who catch the species for illegal pet trade and for harvesting the carapace. Due to overharvesting of its meat, habitat destruction and collection for exotic pet trade, there is dire need for federal protection. The species has therefore been listed as ‘Threatened’ in several regions of the United States where illegal hunting of alligator snappers have been banned.
Closeup head Alligator Snapping Turtle
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Image credits: Jeff Grabert/Shutterstock
It was in July 2012 that many scientists like E.O. Wilson, Kenneth Krysko and Thomas Lovejoy petitioned for federal protection of the species. According to a recent study, the population of alligator snappers in Iowa, Illinois, Tennessee, Missouri and Kentucky has faced massive decline over the years. There are still many illegal tradesmen who commercially exploit the species causing instability of the alligator snappers population. An alarming fact is that much of their habitat has been drained of its resources and converted into croplands, thereby limiting their distribution.
Conservation
According to the IUCN Red List, the species is listed as ‘Threatened’ and has been given protection after it was placed in the CITES Appendix II on June 14, 2006. The Florida Fish & Wildlife Conservation Commission currently lists the species of ‘Special Concern’ and prohibits its capture from the wild. Apart from illegal hunting, the species also suffers from local threats like incidental trawling, nest predation, water pollution and riverine habitat alteration. Habitat loss has affected the breeding cycle of the species causing a decrease in the population and degeneration of the gene pool. However, the Imperiled Species Management Plan led by the F.A.C focuses on controlling the population in Florida by introducing strategic methods for improving water quality, conserving private lands that border their habitat and several other activities. Recently the state of Illinois has been reintroduced the species to strategic watersheds that have been constructed to preserve its native gene pool.
Funfacts
- Alligator snapping turtles can stay submerged underwater for a period of 40 – 50 minutes before they emerge for air.
- They are the only species of turtles that are known to preserve a predatory lure adaptation in their mouths.
- The oldest alligator snapping turtle that was bred under captive care is known to have lived for 70 years.
- Unlike most snapping turtles, the alligator snapping turtle has eyes that are located on the sides of its head.
- As soon as the prey enters an alligator snapper’s mouth, it will either swallow it whole or slice it in two halves using its strong jaws.
- Alligator snappers are the largest freshwater turtles in the United States.
- Alligator snappers are considered ‘in need of conservation’ in the city of Kansas.
- The Alligator snapper has a triangular head, rocky built, dorsal ridges and little bumps that look like eyelashes, giving it a prehistoric look.
- Alligator snappers should never be picked by their tails since it causes massive damage to their spinal cord.
