Contents
The alligator snapping turtle (Macrochelys temminckii) is one of the largest freshwater turtles in the world, distinguished by its thorny appearance, powerful jaws, and special hunting techniques. Native to the southeastern United States, this turtle is a fascinating species that has captivated the interest of herpetologists and wildlife enthusiasts alike.
The alligator snapping turtle is a remarkable species that has managed to survive for millions of years largely unchanged. Its unique adaptations, impressive size, and fascinating behavior make it a subject of interest for scientists. Conservation efforts are crucial to ensure that future generations can continue to marvel at this extraordinary turtle. Protecting habitats and regulating human activities are key to preserving these “living fossils” and maintaining the ecological balance in their natural environments.
Physical Characteristics
The alligator snapping turtle is often described as a “living fossil” due to its ancient lineage and distinctive, rugged appearance. Its physical characteristics include:
- Shell and Body: The turtle’s shell is heavily ridged with three distinct rows of spikes or “scutes” running down its length, giving it a spiky, armored appearance. The color of the shell ranges from dark brown to almost black, often covered with algae that provide camouflage in their murky environments.
- Head and Jaws: The turtle has a large head with a hooked beak-like jaw that is extremely powerful, capable of exerting significant pressure. The head is so large that it cannot retract into its shell like many other turtles. The turtle’s eyes are small and positioned on the sides of the head, giving it a broad field of vision.
How Big Can an Alligator Snapping Turtle Grow?
This species continue to grow throughout its life, so old specimens can be very large and heavy. In the wild, adult alligator snapping turtles usually have a carapace lenght within the 35-80 cm range (roughly 14-30 in) and weigh anywhere from 8 to 80 kg (roughly 20-175 lb). Males tend to grow larger than females, and specimens that exceed 45 kg (99 lb) in weight are usually old males.
- There is an unverified report of an alligator snapping turtle found in Kansas in 1937 weighing 403 lb (183 kg).
- An alligator snapping turtle living in captivity at the Shedd Aquarium in Chicago weighed 249 lb (113 kg) at the age of 16.
Distribution
Alligator snapping turtles are found in the southeastern part of the United States, from Florida and Texas in the south and as far north as Illinois. They are normally only found in bodies of water that eventually drains into the Gulf of Mexico, and do not usually appear in isolated ponds or other isolated bodies of water.
The Oregon specimen
In October 2013, an alligator snapping turtle was found in the Prineville Reservoir in Oregon, in the Pacific Northwest region of the United States. Since the Oregon Department of Fish and Wildlife considers it an invasive species in Oregon, it was caught and killed.
Habitat and Behaviour
M. temminckii is a freshwater species and its prefered habitats are slow-moving rivers, canals, swamps, lakes, and backwaters with abundant vegetation and a soft, muddy bottom. These environments offer the turtles the cover they need for hunting and protection. They prefer waters that are shaded by a tree canopy, shrubs, etcetera, and they also have a fondness for environments with dead submerged trees and beaver dens.
The average home range for an individual is 750 square metres, and females have larger home ranges than the males. Within its home range, the turtle will seek out specific core sites over and over again.
It is unusual for alligator snapping turtles to venture onto land, with the exception of nesting females. Since alligator snapping turtles are not normally seen basking in the sun, experts have suggested that maybe they are thermoregulating by moving to warmer or colder water in the water column.
Diet and Hunting
Alligator snapping turtles are opportunistic predators with a diet that primarily consists of fish, but they are also known to consume a wide variety of other aquatic animals, including frogs, snakes, small alligators, and even other turtles.
They are ambush predators and the turtle often lies motionless on the riverbed with its jaws open wide. Inside its mouth is a worm-like appendage (on the turtle´s tongue) and it wiggles this vermiform appendage to lure in unsuspecting prey. Animals, mistaking the appendage for an actual worm, swim into the turtle’s mouth, where they are quickly captured by its powerful jaws. The inside of the turtle´s mouth is well camouflaged as to not arouse suspicion. This type of hunting is known as aggressive mimicry.
Besides live prey, alligator snapping turtles are also known to scavenge, feeding on carrion when the opportunity arises. This adaptability in diet allows them to survive in a variety of conditions. Within an ecosystem, alligator snapping turtles can fill many roles – from apex predators to opportunistic scavangers.
Reproduction and Life Cycle
Alligator snapping turtles reach sexual maturity at around 11-13 years of age. They will normally become sexually mature when they weigh around 18 lb (8 kg) and the straight carapace lenght is around 13 in (33 cm).
Mating typically occurs in the spring, with females laying eggs in late spring or early summer. Here’s a closer look at their reproductive process:
- Nesting: Females lay clutches of 10-50 eggs in sandy or muddy soil, typically near water sources. The nest is then covered with soil and left to incubate naturally. The incubation period varies, generally lasting between 100 and 140 days.
- Hatching: The sex of the hatchlings is temperature-dependent, with warmer temperatures typically producing more females and cooler temperatures resulting in more males. Once the eggs hatch, the young turtles make their way to the water, where they begin their life in the wild.
Alligator snapping turtles are long-lived creatures, with lifespans often exceeding 50 years in the wild, and some individuals have been known to live over 100 years.
Conservation Status
The alligator snapping turtle is currently listed as a species of concern due to various threats that have led to a decline in their populations. The IUCN 2.3 lists the species as Vulnerable.
- Habitat Destruction: Wetland drainage, damming of rivers, and pollution have significantly reduced the turtle’s natural habitats.
- Overharvesting: These turtles were historically harvested heavily for their meat, which led to significant population declines. Although there are now regulations in place to protect them, illegal poaching still poses a threat.
- Pet Trade: Collecting turtles for the exotic pet trade is a problem for this species.
Conservation programs have been implemented to protect alligator snapping turtles, including habitat restoration projects, captive breeding, and reintroduction programs. Efforts to monitor and manage populations are ongoing.
Several states have legal protection in place for wild alligator snapping turtles. It is protected by state law in Indiana, Illinois, Kentucky, and Missouri, where it is considered endangered. In Kansas, it is considered ”in need of conservation”.
The alligator snapping turtle is a CITES Appendix II species, which means that the international trade – including not just living turtles but also dead ones, turtle parts and turtle derivatives – is regulated by the CITES permit system.
Interaction with Humans
Alligator snapping turtles are generally reclusive and not aggressive toward humans unless provoked. However, due to their powerful bite, they should be approached with caution. These turtles are admired for their unique appearance and behavior, but they are best appreciated from a safe distance in the wild.
Why is it called alligator snapping turtle?
- It is called ”snapping” because of how it hunts with its extremely powerful jaws.
- It is called ”alligator” because the distinctive ridges on the shell are a bit similar to the skin ridges of an alligator.
In parts of the United States, M. temminckii is known as the loggerhead snapper, but this name can cause confusion with the loggerhead musk turtle and the loggerhead sea turtle.